11. Ferramentas Gerais

11.1. Conteúdo da ajuda

Sempre que precisar de ajuda sobre um tópico específico, você pode acessar a página correspondente no Manual do Usuário atual, através do botão Ajuda, disponível na maioria das caixas de diálogo — por favor, observe que plugins de terceiros podem apontar para páginas da web dedicadas.

11.2. Painéis

By default, QGIS provides many panels to work with. Some of these panels are described below while others may be found in different parts of the document. A complete list of default panels provided by QGIS is available via the View ► Panels ► menu and mentioned at Painéis.

11.2.1. Painel Camadas

The Layers panel (also called the map legend) lists all the layers in the project and helps you manage their visibility. You can show or hide it by pressing Ctrl+1. A layer can be selected and dragged up or down in the legend to change the Z-ordering. Z-ordering means that layers listed nearer the top of the legend are drawn over layers listed lower down in the legend.


The Z-ordering behavior can be overridden by the Layer Order panel.

At the top of the Layers panel, a toolbar allows you to:

  • symbology Open the layer styling dock (F7): toggle the layer styling panel on and off.

  • addGroup Add new group

  • showMapTheme Manage Map Themes: control visibility of layers and arrange them in different map themes.

  • filterMap Filter Legend by Map Content: only the layers that are set visible and whose features intersect the current map canvas have their style rendered in the layers panel. Otherwise, a generic NULL symbol is applied to the layer. Based on the layer symbology, this is a convenient way to identify which kind of features from which layers cover your area of interest.

  • expressionFilter Filter Legend by Expression: apply an expression to remove styles from the selected layer tree that have no feature satisfying the condition. This can be used to highlight features that are within a given area/feature of another layer. From the drop-down list, you can edit and clear the expression currently applied.

  • expandTree Expand All or collapseTree Collapse All layers and groups in the layers panel.

  • removeLayer Remove Layer/Group currently selected.


Fig. 11.1 Layer Toolbar in Layers Panel


Tools to manage the layers panel are also available for map and legend items in print layouts Configuring map themes

The showMapTheme Manage Map Themes drop-down button provides access to convenient shortcuts to manipulate visibility of the layers in the Layers panel:

  • showAllLayers Mostrar Todas as Camadas

  • hideAllLayers Ocultar Todas as Camadas

  • showSelectedLayers Mostrar Camadas Selecionadas

  • hideSelectedLayers Ocultar Camadas Selecionadas

  • toggleSelectedLayers Toggle Selected Layers: changes the visibility of the first selected layer in the panel, and applies that state to the other selected layers. Also accesible through Space shortcut.

  • Toggle Selected Layers Independently: changes the visibility status of each selected layer

  • hideDeselectedLayers Ocultar Camadas Não Selecionadas

Beyond the simple control of layer visibility, the showMapTheme Manage Map Themes menu allows you to configure Map Themes in the legend and switch from one map theme to another. A map theme is a snapshot of the current map legend that records:

  • the layers set as visible in the Layers panel

  • and for each visible layer:

    • the reference to the style applied to the layer

    • the visible classes of the style, ie the layer checked node items in the Layers panel. This applies to symbologies other than the single symbol rendering

    • the collapsed/expanded state of the layer node(s) and the group(s) it’s placed inside

To create a map theme:

  1. Check a layer you want to show

  2. Configure the layer properties (symbology, diagram, labels…) as usual

  3. Expand the Style ► menu at the bottom and click on Add… to store the settings as a new style embedded in the project


    A map theme does not remember the current details of the properties: only a reference to the style name is saved, so whenever you apply modifications to the layer while this style is enabled (eg change the symbology rendering), the map theme is updated with new information.

  4. Repeat the previous steps as necessary for the other layers

  5. If applicable, expand or collapse groups or visible layer nodes in the Layers panel

  6. Click on the showMapTheme Manage Map Themes button on top of the panel, and Add Theme…

  7. Enter the map theme’s name and click OK

The new theme is listed in the lower part of the showMapTheme drop-down menu.

You can create as many map themes as you need: whenever the current combination in the map legend (visible layers, their active style, the map legend nodes) does not match any existing map theme contents as defined above, click on Add Theme… to create a new map theme, or use Replace Theme ► to update a map theme. You can rename the active map theme with Rename Current Theme… or use the Remove Current Theme button to delete it.

Map themes are helpful to switch quickly between different preconfigured combinations: select a map theme in the list to restore its combination. All configured themes are also accessible in the print layout, allowing you to create different map items based on specific themes and independent of the current main canvas rendering (see Map item layers). Overview of the context menu of the Layers panel

At the bottom of the toolbar, the main component of the Layers panel is the frame listing vector or raster layers added to the project, optionally organized in groups. Depending on the item selected in the panel, a right-click shows a dedicated set of options presented below.


Camada Vetorial

Camada Raster


zoomToLayer Zoom to Layer/Group




zoomToLayer Zoom to Selection


inOverview Mostrar em Visão Geral



Show Feature Count


Copy Layer/Group




Rename Layer/Group




zoomActual Zoom to Native Resolution (100%)


Stretch Using Current Extent


dbManager Atualizar Camada SQL…


addGroup Add Group


duplicateLayer Duplicate Layer



removeLayer Remove Layer/Group…




Move Out of Group



Move to Top




Move to Bottom




Check and all its Parents



Group Selected



openTable Abrir Tabela de Atributos


toggleEditing Alternar Edição


allEdits Edições Atuais ►




Change Data Source…


Repair Data Source…


Actions on selections ► (in edit mode)


► Duplicate Feature


► Duplicate Feature and Digitize


Set Layer Scale Visibility…



Zoom para escala visível



Set CRS ►



► Set Layer/Group CRS…




► Set Project CRS from Layer



Set Group WMS Data…


unchecked Mutually Exclusive Group


Check and all its children (Ctrl-click)


Uncheck and all its children (Ctrl-click)


Make Permanent


Exportar ►




► Save As…


► Save Features As…


► Save Selected Features As…


► Save As Layer Definition File…




► Save As QGIS Layer Style File…



Estilos ►



► Copy Style



► Paste Style




► Add…



► Rename Current…



► Edit symbol…


► Copy Symbol


► Paste Symbol





Table: Context menu from Layers Panel items

For GRASS vector layers, toggleEditing Toggle editing is not available. See section Digitalizando e editando uma camada vetorial GRASS for information on editing GRASS vector layers. Interact with groups and layers

Layers in the legend window can be organized into groups. There are two ways to do this:

  1. Press the folder icon to add a new group. Type in a name for the group and press Enter. Now click on an existing layer and drag it onto the group.

  2. Select some layers, right-click in the legend window and choose Group Selected. The selected layers will automatically be placed in a new group.

To move a layer out of a group, drag it out, or right-click on it and choose Move Out of Group: the layer is moved from the group and placed above it. Groups can also be nested inside other groups. If a layer is placed in a nested group, Move Out of Group will move the layer out of all nested groups.

To move a group or layer to the top of the layer panel, either drag it to the top, or choose Move to Top. If you use this option on a layer nested in a group, the layer is moved to the top in its current group. The Move to Bottom option follows the same logic to move layers and groups down.

The checkbox for a group will show or hide the checked layers in the group with one click. With Ctrl pressed, the checkbox will also turn on or off all the layers in the group and its sub-groups.

Ctrl-click on a checked / unchecked layer will uncheck / check the layer and all its parents.

Enabling the Mutually Exclusive Group option means you can make a group have only one layer visible at the same time. Whenever a layer within the group is set visible the others will be toggled not visible.

É possível selecionar mais de uma camada ou grupo ao mesmo tempo mantendo pressionada a tecla Ctrl enquanto clica em camadas adicionais. Você pode mover todas as camadas selecionadas para um novo grupo ao mesmo tempo.

You may also delete more than one layer or group at once by selecting several items with the Ctrl key and then pressing Ctrl+D: all selected layers or groups will be removed from the layers list.

More information on layers and groups using indicator icon

In some circumstances, icons appears next to the layer or group in the Layers panel to give more information about the layer/group. These symbols are:

  • toggleEditing to indicate that the layer is in edit mode and you can modify the data

  • editableEdits to indicate that the layer being edited has some unsaved changes

  • indicatorFilter to indicate a filter applied to the layer. Hover over the icon to see the filter expression and double-click to update the setting

  • indicatorNonRemovable to identify layers that are required in the project, hence non removable

  • indicatorEmbedded to identify an embedded group or layer and the path to their original project file

  • indicatorBadLayer to identify a layer whose data source was not available at the project file opening (see Handling broken file paths). Click the icon to update the source path or select Repair Data Source… entry from the layer contextual menu.

  • indicatorMemory to remind you that the layer is a temporary scratch layer and its content will be discarded when you close this project. To avoid data loss and make the layer permanent, click the icon to store the layer in any of the OGR vector formats supported by QGIS.

  • indicatorNoCRS to identify a layer that has no/unknown CRS

  • indicatorTemporal to identify a temporal layer controlled by canvas animation Editing vector layer style

From the Layers panel, you have shortcuts to change the layer rendering quickly and easily. Right-click on a vector layer and select Styles ► in the list in order to:

  • see the styles currently applied to the layer. If you defined many styles for the layer, you can switch from one to another and your layer rendering will automatically be updated on the map canvas.

  • copy part or all of the current style, and when applicable, paste a copied style from another layer


    Quickly share a layer style

    From the context menu, copy the style of a layer and paste it to a group or a selection of layers: the style is applied to all the layers that are of the same type (vector/raster) as the original layer and, for vector layers, have the same geometry type (point, line or polygon).

  • rename the current style, add a new style (which is actually a copy of the current one) or delete the current style (when multiple styles are available).


The previous options are also available for raster or mesh layers.

  • update the symbol color using a Color Wheel. For convenience, the recently used colors are also available at the bottom of the color wheel.

  • Edit Symbol…: open the Symbol Selector dialog and change feature symbol (symbol, size, color…).

When using a classification symbology type (based on categorized, graduated or rule-based), the aforementioned symbol-level options are available from the class entry context menu. Also provided are the toggleAllLayers Toggle Items, showAllLayers Show All Items and hideAllLayers Hide All Items entries to switch the visibility of all the classes of features. These avoid (un)checking items one by one.


Double-clicking a class leaf entry also opens the Symbol Selector dialog.

11.2.2. Painel de Estilo de Camada

O painel Estilo de Camada (também ativado com Ctrl+3) é um atalho para algumas das funcionalidades da caixa de diálogo Pripriedades da Camada. Ele fornece uma maneira rápida e fácil de definir a renderização e o comportamento de uma camada e visualizar seus efeitos sem precisar abrir a caixa de diálogo de propriedades da camada.

In addition to avoiding the blocking (or “modal”) layer properties dialog, the layer styling panel also avoids cluttering the screen with dialogs, and contains most style functions (color selector, effects properties, rule edit, label substitution…): e.g., clicking color buttons inside the layer style panel causes the color selector dialog to be opened inside the layer style panel itself rather than as a separate dialog.

From a drop-down list of current layers in the layer panel, select an item and:

  • Depending on the layer type, set:

  • Manage the associated style(s) in the stylePreset Style Manager (more details at Managing Custom Styles).

  • See the history History of changes you applied to the layer style in the current project: you can therefore cancel or restore to any state by selecting it in the list and clicking Apply.

For Vector Tile layers there is an option to show checkbox Visible rules only. This is very useful if you just want to work with rules that fall inside the current map canvas zoom level.

Another powerful feature of this panel is the checkbox Live update checkbox. Tick it to render your changes immediately on the map canvas: you no longer need to click the Apply button.


Fig. 11.2 Defining a layer’s symbology from the layer styling panel

11.2.3. Layer Order Panel

By default, layers shown on the QGIS map canvas are drawn following their order in the Layers panel: the higher a layer is in the panel, the higher (hence, more visible) it’ll be in the map view.

You can define a drawing order for the layers independent of the order in the layers panel with the Layer Order panel enabled in View ► Panels ► menu or with Ctrl+9. Check checkbox Control rendering order underneath the list of layers and reorganize the layers in the panel as you want. This order becomes the one applied to the map canvas. For example, in Fig. 11.3, you can see that the airports features are displayed over the alaska polygon despite those layers’ respective placement in the Layers panel.

Unchecking checkbox Control rendering order will revert to default behavior.


Fig. 11.3 Define a layer order independent of the legend

11.2.4. Overview Panel

The Overview panel (Ctrl+8) displays a map with a full extent view of some of the layers. The Overview map is filled with layers using the Show in Overview option from the Layer menu or in the layer contextual menu. Within the view, a red rectangle shows the current map canvas extent, helping you quickly to determine which area of the whole map you are currently viewing. If you click-and-drag the red rectangle in the overview frame, the main map view extent will update accordingly.

Note that labels are not rendered to the map overview even if the layers used in the map overview have been set up for labeling.

11.2.5. Log Messages Panel

When loading or processing some operations, you can track and follow messages that appear in different tabs using the messageLog Log Messages Panel. It can be activated using the most right icon in the bottom status bar.

11.2.6. Undo/Redo Panel

For each layer being edited, the Undo/Redo (Ctrl+5) panel shows the list of actions carried out, allowing you quickly to undo a set of actions by selecting the action listed above. More details at Undo and Redo edits.

11.2.7. Statistical Summary Panel

The Statistics panel (Ctrl+6) provides summarized information on any vector layer. This panel allows you to select:

  • the vector layer to compute the statistics on

  • the column to use, or an expression expression

  • the statistics to return using the drop-down button at the bottom-right of the dialog. Depending on the field’s (or expression’s values) type, available statistics are:



Número inteiro








Count Distinct Value



Count Missing value












Desvio Padrão



Desvio Padrão na Amostra



Valor mínimo





Valor máximo




















Primeiro Quartil



Terceiro Quartil



Inter Quartile Range



Comprimento Mínimo


Comprimento Máximo


Mean Length


Table: Statistics available for each field type

The statistical summary can be:

  • returned for the whole layer or checkbox selected features only

  • recalculated using the refresh button when the underlying data source changes (eg, new or removed features/fields, attribute modification)

  • editCopy copied to the clipboard and pasted as a table in another application


Fig. 11.4 Show statistics on a field

11.3. Projetos animados

Sometimes, you’d like to keep some layers in different projects, but with the same style. You can either create a default style for these layers or embed them from another project to save time and effort.

Embed layers and groups from an existing project has some advantages over styling:

  • All types of layers (vector or raster, local or online…) can be added

  • Fetching groups and layers, you can keep the same tree structure of the “background” layers in your different projects

  • While the embedded layers are editable, you can’t change their properties such as symbology, labels, forms, default values and actions, ensuring consistency across projects

  • Modifique os itens no projeto original e as alterações são propagadas para todos os outros projetos

If you want to embed content from other project files into your project, select Layer ► Embed Layers and Groups:

  1. Click the button to look for a project: you can see the content of the project (see Fig. 11.5)

  2. Hold down Ctrl ( or osx Cmd) and click on the layers and groups you wish to retrieve

  3. Clique OK.

The selected layers and groups are embedded in the Layers panel and displayed on the map canvas. An indicatorEmbedded icon is added next to their name for recognition and hovering over displays a tooltip with the original project file path.


Fig. 11.5 Select layers and groups to embed

Like any other layer, an embedded layer can be removed from the project by right-clicking on the layer and clicking removeLayer Remove.


Change rendering of an embedded layer

It’s not possible to change the rendering of an embedded layer, unless you make the changes in the original project file. However, right-clicking on a layer and selecting Duplicate creates a layer which is fully-featured and not dependent on the original project. You can then safely remove the linked layer.

11.4. Working with the map canvas

11.4.1. Renderização

By default, QGIS renders all visible layers whenever the map canvas is refreshed. The events that trigger a refresh of the map canvas include:

  • adding a layer

  • panning or zooming

  • redimensionando a janela QGIS

  • changing the visibility of a layer or layers

QGIS permite controlar o processo de renderização de várias formas. Escala dependente da renderização

Scale-dependent rendering allows you to specify the minimum and maximum scales at which a layer (raster or vector) will be visible. To set scale-dependent rendering, open the Properties dialog by double-clicking on the layer in the legend. On the Rendering tab, tick checkbox Scale dependent visibility and enter the Minimum (exclusive) and Maximum (inclusive) scale values.

You can also activate scale dependent visibility on a layer from the Layers panel. Right-click on the layer and in the context menu, select Set Layer Scale Visibility.

The mapIdentification Set to current canvas scale button allow you to use the current map canvas scale as boundary of the range visibility.


When a layer is not rendered in the map canvas because the map scale is out of its visibility scale range, the layer is greyed in the Layers panel and a new option Zoom to Visible Scale appears in the layer context menu. Select it and the map is zoomed to the layer’s nearest visibility scale. Controlando a renderização do mapa

Map rendering can be controlled in various ways, as described below.

Suspensão de edição

To suspend rendering, click the checkbox Render checkbox in the bottom-right corner of the status bar. When checkbox Render is not checked, QGIS does not redraw the canvas in response to any of the events described in the section Renderização. Examples of when you might want to suspend rendering include:

  • adding many layers and symbolizing them prior to drawing

  • adding one or more large layers and setting scale dependency before drawing

  • adding one or more large layers and zooming to a specific view before drawing

  • any combination of the above

Caixa de seleção checkbox :guilabel: caixa de seleção Renderizar permite renderização e causa uma atualização imediata na tela do mapa.

Opções de adicionar configurações da camada

Você pode definir uma opção para sempre carregar novas camadas sem desenhá-las. Isso significa que a camada será adicionada ao mapa, mas sua caixa de seleção de visibilidade na legenda estará desmarcada por padrão. Para definir esta opção, escolha a opção de menu Configurações ► Opções e clique na guia Renderizar. Desmarque checkbox Por padrão, novas camadas adicionadas ao mapa devem ser exibidas. Qualquer camada adicionada posteriormente ao mapa ficará desativada (invisível) por padrão.

Parar rendirização

To stop the map drawing, press the Esc key. This will halt the refresh of the map canvas and leave the map partially drawn. It may take a bit of time between pressing Esc for the map drawing to halt.

Influência da qualidade da edição

QGIS has an option to influence the rendering quality of the map. Choose menu option Settings ► Options, click on the Rendering tab and select or deselect checkbox Make lines appear less jagged at the expense of some drawing performance.

Acelerando a visualização

There are some settings that allow you to improve rendering speed. Open the QGIS options dialog using Settings ► Options, go to the Rendering tab and select or deselect the following checkboxes:

  • checkbox Use render caching where possible to speed up redraws.

  • checkbox Render layers in parallel using many CPU cores and then set the checkbox Max cores to use.

  • The map renders in the background onto a separate image and each checkbox Map Update interval, the content from this (off-screen) image will be taken to update the visible screen representation. However, if rendering finishes faster than this duration, it will be shown instantaneously.

  • With checkbox Enable Feature simplification by default for newly added layers, you simplify features’ geometry (fewer nodes) and as a result, they display more quickly. Be aware that this can cause rendering inconsistencies.

11.4.2. Zooming and Panning

There are multiple ways to zoom and pan to an area of interest. You can use the Map Navigation toolbar, the mouse and keyboard on the map canvas and also the menu actions from the View menu and the layers’ contextual menu in the Layers panel.




View menu

Map Navigation Toolbar

Layer Contextual Menu


Pan Map

When activated, left click anywhere on the map canvas to pan the map at the cursor position. You can also pan the map by holding down the left mouse button and dragging the map canvas.




Zoom In

When activated, left click anywhere on the map canvas to zoom in one level. The mouse cursor position will be the center of the zoomed area of interest. You can also zoom in to an area by dragging a rectangle on the map canvas with the left mouse button.




Zoom Out

When activated, left click anywhere on the map canvas to zoom out one level. The mouse cursor position will be the center of the zoomed area of interest. You can also zoom out from an area by dragging a rectangle on the map canvas with the left mouse button.




Pan Map to Selection

Pan the map to the active layer’s selected features.




Zoom To Selection

Zoom to the active layer’s selected features.





Zoom To Layer

Zoom to the active layer’s extent.





Zoom Full

Zoom to the extent of all the layers in the project.




Zoom Last

Zoom the map to the previous extent in history.




Zoom Next

Zoom the map to the next extent in history.




Zoom to Native Resolution

Zoom the map to a level where one pixel of the active raster layer covers one screen pixel.




A Zoom factor can be set under the Settings ► options Options ► Map tools menu to define the scale behavior while zooming. There, you can also set a list of Predefined Scales that will be available at the bottom of the map canvas. With the Mouse on the Map Canvas

In addition to using the pan Pan zoomIn Zoom In and zoomOut Zoom Out tools described above, you can hold the mouse wheel inside of the map canvas and drag the mouse cursor (on macOS, you may need to hold down the cmd key). You can also roll the mouse wheel to zoom in and out on the map. The mouse cursor position will be the center of the zoomed area of interest. Holding down Ctrl while rolling the mouse wheel results in a finer zoom. With the Keyboard on the Map Canvas

Holding down spacebar on the keyboard and moving the mouse cursor will pan the map the same way dragging the map canvas with pan Pan does.

Panning the map is possible with the arrow keys. Place the mouse cursor inside the map area, and press on the arrow keys to pan up, down, left and right.

The PgUp and PgDown keys on the keyboard will cause the map display to zoom in or out following the zoom factor set. Pressing Ctrl++ or Ctrl+- also performs an immediate zoom in/out on the map canvas.

When certain map tools are active (Identify, Measure…), you can perform a zoom by holding down Shift and dragging a rectangle on the map to zoom to that area. This is not enabled for selection tools (since they use Shift for adding to selection) or edit tools.

11.4.3. Favoritos Espaciais

Spatial Bookmarks allow you to “bookmark” a geographic location and return to it later. By default, bookmarks are saved in the user’s profile (as User Bookmarks), meaning that they are available from any project the user opens. They can also be saved for a single project (named Project Bookmarks) and stored within the project file, which can be helpful if the project is to be shared with other users. Novo Favorito

Para criar um novo favorito:

  1. Zoom and pan to the area of interest.

  2. Select the menu option View ► newBookmark New Spatial Bookmark…, press Ctrl+B or right-click the showBookmarks Spatial Bookmarks entry in the Browser panel and select New Spatial Bookmark. The Bookmark Editor dialog opens.


    Fig. 11.6 The Bookmark Editor Dialog

  3. Enter a descriptive name for the bookmark

  4. Enter or select a group name in which to store related bookmarks

  5. Select the extent of the area you wish to save, using the extent selector; the extent can be calculated from a loaded layer extent, the current map canvas or drawn over the current map canvas.

  6. Indicate the CRS to use for the extent

  7. Select whether the bookmark will be Saved in User Bookmarks or Project Bookmarks

  8. Press Save to add the bookmark to the list

Note que você pode ter vários favoritos com o mesmo nome. Trabalhando com favoritos

To use and manage bookmarks, you can either use the Spatial Bookmarks panel or Browser.

Select View ► showBookmarks Show Spatial Bookmark Manager or press Ctrl+7 to open the Spatial Bookmarks Manager panel. Select View ► showBookmarks Show Bookmarks or Ctrl+Shift+B to show the showBookmarks Spatial Bookmarks entry in the Browser panel.

You can perform the following tasks:


Spatial Bookmark Manager


Zoom to a Bookmark

Double-click on it, or select the bookmark and press the zoomToBookmark Zoom to bookmark button.

Double-click on it, drag and drop it to the map canvas, or right-click the bookmark and select Zoom to Bookmark.

Delete a bookmark

Select the bookmark and click the deleteSelected Delete bookmark button. Confirm your choice.

Right-click the bookmark and select Delete Spatial Bookmark. Confirm your choice.

Export bookmarks to XML

Click the sharing Import/Export Bookmarks button and select sharingExport Export. All the bookmarks (user or project) are saved in an xml file.

Select one or more folders (user or project) or subfolders (groups), then right-click and select sharingExport Export Spatial Bookmarks…. The selected bookmark subset is saved.

Import bookmarks from XML

Click the sharing Import/Export Bookmarks button and select sharingImport Import. All bookmarks in the XML file are imported as user bookmarks.

Right-click the Spatial Bookmarks entry or one of its folders (user or project) or subfolders (groups) to determine where to import the bookmarks, then select sharingImport Import Spatial Bookmarks. If performed on the Spatial Bookmarks entry, the bookmarks are added to User Bookmarks.

Edit bookmark

You can change a bookmark by changing the values in the table. You can edit the name, the group, the extent and if it is stored in the project or not.

Right-click the desired bookmark and select Edit Spatial Bookmark…. The Bookmark Editor will open, allowing you to redefine every aspect of the bookmark as if you were creating it for the first time.

You can also drag and drop the bookmark between folders (user and project) and subfolders (groups).

You can also zoom to bookmarks by typing the bookmark name in the locator.

11.4.4. Decorações

Decorations include Grid, Title Label, Copyright Label, Image, North Arrow, Scale Bar and Layout Extents. They are used to ‘decorate’ the map by adding cartographic elements. Malha

addGrid Grid allows you to add a coordinate grid and coordinate annotations to the map canvas.

  1. Select menu option View ► Decorations ► Grid… to open the dialog.


    Fig. 11.7 The Grid Dialog

  2. Tick checkbox Enable grid and set grid definitions according to the layers loaded in the map canvas:

    • The Grid type: it can be Line or Marker

    • The associated Line symbol or marker symbol used to represent the grid marks

    • The Interval X and Interval Y between the grid marks, in map units

    • An Offset X and Offset Y distance of the grid marks from the bottom left corner of the map canvas, in map units

    • The interval and offset parameters can be set based on the:

      • Canvas Extents: generates a grid with an interval that is approximatively 1/5 of the canvas width

      • Active Raster Layer resolution

  3. Tick checkbox Draw annotations to display the coordinates of the grid marks and set:

    • The Annotation direction, ie how the labels would be placed relative to their grid line. It can be:

      • Horizontal or Vertical for all the labels

      • Horizontal and Vertical, ie each label is parallel to the grid mark it refers to

      • Boundary direction, ie each label follows the canvas boundary, and is perpendicular to the grid mark it refers to

    • The Annotation font (text formatting, buffer, shadow…) using the font selector widget

    • The Distance to map frame, margin between annotations and map canvas limits. Convenient when exporting the map canvas eg to an image format or PDF, and avoid annotations to be on the “paper” limits.

    • The Coordinate precision

  4. Click Apply to verify that it looks as expected or OK if you’re satisfied. Title Label

titleLabel Title Label allows you to decorate your map with a Title.

To add a Title Label decoration:

  1. Select menu option View ► Decorations ► Title Label… to open the dialog.


    Fig. 11.8 The Title Decoration Dialog

  2. Make sure checkbox Enable Title Label is checked

  3. Enter the title text you want to place on the map. You can make it dynamic using the Insert or Edit an Expression… button.

  4. Choose the Font for the label using the font selector widget with full access to QGIS text formatting options. Quickly set the font color and opacity by clicking the black arrow to the right of the font combo box.

  5. Select the color to apply to the title’s Background bar color.

  6. Choose the Placement of the label in the canvas: options are Top left, Top Center (default), Top Right, Bottom left, Bottom Center and Bottom Right.

  7. Refine the placement of the item by setting a horizontal and/or vertical Margin from Edge. These values can be in Millimeters or Pixels or set as a Percentage of the width or height of the map canvas.

  8. Click Apply to verify that it looks as expected or OK if you’re satisfied. Image Decoration

addImage Image allows you to add an image (logo, legend, ..) on the map canvas.

To add an image:

  1. Select menu option View ► Decorations ► Image… to open the dialog.


    Fig. 11.10 The Image Decoration Dialog

  2. Make sure checkbox Enable Image is checked

  3. Select a bitmap (e.g. png or jpg) or SVG image using the Browse button

  4. If you have chosen a parameter enabled SVG then you can also set a Fill or Stroke (outline) color. For bitmap images, the color settings are disabled.

  5. Set a Size of the image in mm. The width of selected image is used to resize it to given Size.

  6. Choose where you want to place the image on the map canvas with the Placement combo box. The default position is Top Left.

  7. Set the Horizontal and Vertical Margin from (Canvas) Edge. These values can be set in Millimeters, Pixels or as a Percentage of the width or height of the map canvas.

  8. Click Apply to verify that it looks as expected and OK if you’re satisfied. Seta Norte

northArrow North Arrow allows you to add a north arrow on the map canvas.

To add a north arrow:

  1. Select menu option View ► Decorations ► North Arrow… to open the dialog.


    Fig. 11.11 The North Arrow Dialog

  2. Make sure checkbox Enable north arrow is checked

  3. Optionally change the color and size, or choose a custom SVG

  4. Optionally change the angle or choose Automatic to let QGIS determine the direction

  5. Optionally choose the placement from the Placement combo box

  6. Optionally refine the placement of the arrow by setting a horizontal and/or vertical Margin from (Canvas) Edge. These values can be in Millimeters or Pixels or set as a Percentage of the width or height of the map canvas.

  7. Click Apply to verify that it looks as expected and OK if you’re satisfied. Barra de Escala

scaleBar Scale Bar adds a simple scale bar to the map canvas. You can control the style and placement, as well as the labelling of the bar.

QGIS only supports displaying the scale in the same units as your map frame. So, if the units of your project’s CRS are meters, you can’t create a scale bar in feet. Likewise, if you are using decimal degrees, you can’t create a scale bar to display distance in meters.

Para adicionar uma barra de escala:

  1. Select menu option View ► Decorations ► Scale Bar… to open the dialog


    Fig. 11.12 The Scale Bar Dialog

  2. Make sure checkbox Enable scale bar is checked

  3. Choose a style from the Scale bar style selectString combo box

  4. Select the Color of bar selectColor by choosing a fill color (default: black) and an outline color (default: white). The scale bar fill and outline can be made opaque by clicking on the down arrow to the right of the color input.

  5. Selecione a fonte para a barra de escala na caixa Fonte da barra selectString

  6. Set the Size of bar selectNumber

  7. Optionally check checkbox Automatically snap to round number on resize to display easy-to-read values

  8. Choose the placement from the Placement selectString combo box

  9. You can refine the placement of the item by setting a horizontal and/or vertical Margin from (Canvas) Edge. These values can be in Millimeters or Pixels or set as a Percentage of the width or height of the map canvas.

  10. Click Apply to verify that it looks as expected or OK if you’re satisfied. Layout Extents

addMap Layout Extents adds the extents of map item(s) in print layout(s) to the canvas. When enabled, the extents of all map items within all print layouts are shown using a lightly dotted border labeled with the name of the print layout and map item. You can control the style and labeling of the displayed layout extents. This decoration is useful when you are tweaking the positioning of map elements such as labels, and need to know the actual visible region of print layouts.


Fig. 11.13 Example of layout extents displayed in a QGIS project with two print layouts. The print layout named ‘Sights’ contains two map items, while the other print layout contains one map item.

To add layout extent(s):

  1. Select View ► Decorations ► Layout Extents to open the dialog


    Fig. 11.14 The Layout Extents Dialog

  2. Make sure checkbox Show layout extents is checked.

  3. Optionally change the symbol and labeling of the extents.

  4. Click Apply to verify that it looks as expected and OK if you’re satisfied.


Decorations Settings

When you save a QGIS project file, any changes you have made to Grid, North Arrow, Scale Bar, Copyright and Layout Extents will be saved in the project and restored the next time you load the project.

11.4.5. Ferramentas de anotação

Annotations are information added to the map canvas and shown within a balloon. This information can be of different types and annotations are added using the corresponding tools in the Attributes Toolbar:


Fig. 11.15 Customized QT Designer annotation form

To add an annotation, select the corresponding tool and click on the map canvas. An empty balloon is added. Double-click on it and a dialog opens with various options. This dialog is almost the same for all the annotation types:

  • Na parte superior, um seletor de arquivo para preencher o caminho para um arquivo html, svg ou ui, dependendo do tipo de anotação. Para anotação de texto, você pode inserir sua mensagem em uma caixa de texto e definir sua renderização com as ferramentas de fonte normais.

  • checkbox Fixed map position: when unchecked, the balloon placement is based on a screen position (instead of the map), meaning that it’s always shown regardless the map canvas extent.

  • Linked layer: associates the annotation with a map layer, making it visible only when that layer is visible.

  • Map marker: using QGIS symbols, sets the symbol to display at the balloon anchor position (shown only when Fixed map position is checked).

  • Frame style: sets the frame background color, transparency, stroke color or width of the balloon using QGIS symbols.

  • Contents margins: sets interior margins of the annotation frame.


Fig. 11.16 Annotation text dialog

Annotations can be selected when an annotation tool is enabled. They can then be moved by map position (by dragging the map marker) or by moving only the balloon. The annotation Move Annotation tool also allows you to move the balloon on the map canvas.

To delete an annotation, select it and either press the Del or Backspace button, or double-click it and press the Delete button in the properties dialog.


If you press Ctrl+T while an Annotation tool (move annotation, text annotation, form annotation) is active, the visibility states of the items are inverted.


Layout the map with annotations

You can print or export annotations with your map to various formats using:

  • map canvas export tools available in the Project menu

  • print layout, in which case you need to check Draw map canvas items in the corresponding map item properties

11.4.6. Medição Informação Geral

QGIS provides four means of measuring geometries:

  • interactive measurement tools measure

  • measuring in the calculateField Field Calculator

  • derived measurements in the Identifying Features tool

  • the vector analysis tool: Vector ► Geometry Tools ► Export/Add Geometry Columns

Measuring works within projected coordinate systems (e.g., UTM) and unprojected data. The first three measuring tools behave equally to global project settings:

  • Diferentemente da maioria dos outros GIS, a métrica de medição padrão é elipsoidal, usando o elipsóide definido em Projeto ► Propriedades… ► Geral. Isso ocorre quando os sistemas de coordenadas geográficas e projetadas são definidos para o projeto.

  • If you want to calculate the projected/planimetric area or distance using cartesian maths, the measurement ellipsoid has to be set to “None/Planimetric” (Project ► Properties… ► General). However, with a geographic (ie unprojected) CRS defined for the data and project, area and distance measurement will be ellipsoidal.

However, neither the identify tool nor the field calculator will transform your data to the project CRS before measuring. If you want to achieve this, you have to use the vector analysis tool: Vector ► Geometry Tools ► Add Geometry Attributes…. Here, measurement is planimetric, unless you choose the ellipsoidal measurement. Measure length, areas and angles interactively

Click the measure icon in the Attribute toolbar to begin measurements. The down arrow near the icon switches between measure length, measureArea area or measureAngle angle. The default unit used in the dialog is the one set in Project ► Properties… ► General menu.


Configuring the measure tool

While measuring length or area, clicking the Configuration button at the bottom of the widget opens the Settings ► Options ► Map Tools menu, where you can select the rubberband color, the precision of the measurements and the unit behavior. You can also choose your preferred measurement or angle units, but keep in mind that those values are overridden in the current project by the selection made in the Project ► Properties… ► General menu, and by the selection made in the measurement widget.

All measuring modules use the snapping settings from the digitizing module (see section Configurando a Tolerância de Atracção e Raio de Pesquisa). So, if you want to measure exactly along a line feature, or around a polygon feature, first set its layer snapping tolerance. Now, when using the measuring tools, each mouse click (within the tolerance setting) will snap to that layer.

By default, measure Measure Line measures real distances between given points according to a defined ellipsoid. The tool then allows you to click points on the map. Each segment length, as well as the total, shows up in the measure window. To stop measuring, click the right mouse button. Now it is possible to copy all your line measurements at once to the clipboard using the Copy All button.

Note that you can use the drop-down list near the total to change the measurement units interactively while working with the measure tool (‘Meters’, ‘Kilometers’, ‘Feet’, ‘Yards’, ‘Miles’, ‘Nautical miles’, ‘Centimeters’, ‘Millimeters’, ‘Degrees’, ‘Map units’). This unit is retained for the widget until a new project is created or another project is opened.

The Info section in the dialog explains how calculations are made according to the CRS settings available.


Fig. 11.17 Measure Distance

measureArea Measure Area: Areas can also be measured. In the measure window, the accumulated area size appears. Right-click to stop drawing. The Info section is also available as well as the ability to switch between different area units (‘Square meters’, ‘Square kilometers’, ‘Square feet’, ‘Square yards’, ‘Square miles’, ‘Hectares’, ‘Acres’, ‘Square centimeters’, ‘Square millimeters’, ‘Square nautical miles’, ‘Square degrees’, ‘Map units’).


Fig. 11.18 Measure Area

measureAngle Measure Angle: You can also measure angles. The cursor becomes cross-shaped. Click to draw the first segment of the angle you wish to measure, then move the cursor to draw the desired angle. The measurement is displayed in a pop-up dialog.


Fig. 11.19 Measure Angle

11.5. Interacting with features

11.5.1. Selecionando características

QGIS provides several tools to select features on the map canvas. Selection tools are available in the Edit ► Select menu or in the Selection Toolbar.


Selection tools work with the currently active layer. Selecting manually on the map canvas

To select one or more features with the mouse, you can use one of the following tools:

  • selectRectangle Select Features by area or single click

  • selectPolygon Select Features by Polygon

  • selectFreehand Select Features by Freehand

  • selectRadius Select Features by Radius


Other than selectPolygon Select Features by Polygon, these manual selection tools allow you to select feature(s) on the map canvas with a single click.


Use the selectPolygon Select Features by Polygon tool to use an existing polygon feature (from any layer) to select overlapping features in the active layer. Right-click in the polygon and choose it from the context menu that shows a list of all the polygons that contain the clicked point. All the overlapping features from the active layer are selected.


Use the Edit ► Select ► Reselect Features tool to redo your latest selection. Very useful when you have painstakingly made a selection, and then click somewhere else accidentally and clear your selection.

While using the selectRectangle Select Feature(s) tool, holding Shift or Ctrl toggles whether a feature is selected (ie either adds to the current selection or remove from it).

For the other tools, different behaviors can be performed by holding down:

  • Shift: add features to the current selection

  • Ctrl: subtrai feições da seleção atual

  • Ctrl+Shift: intersect with current selection, ie only keep overlapping features from the current selection

  • Alt: select features that are totally within the selection shape. Combined with Shift or Ctrl keys, you can add or substract features to/from the current selection. Automatic selection

The other selection tools, most of them available from the Attribute table, perform a selection based on a feature’s attribute or its selection state (note that attribute table and map canvas show the same information, so if you select one feature in the attribute table, it will be selected on the map canvas too):

  • expressionSelect Select By Expression… select features using expression dialog

  • formSelect Select Features By Value… or press F3

  • deselectAll Deselect Features from All Layers or press Ctrl+Alt+A to deselect all selected features in all layers

  • deselectActiveLayer Deselect Features from the Current Active Layer or press Ctrl+Shift+A

  • selectAll Select All Features or press Ctrl+A to select all features in the current layer

  • invertSelection Invert Feature Selection to invert the selection in the current layer

  • algorithmSelectLocation Select by Location to select the features based on their spatial relationship with other features (in the same or another layer - see Selecionar pela localização)

For example, if you want to find regions that are boroughs from regions.shp of the QGIS sample data, you can:

  1. Use the expressionSelect Select features using an Expression icon

  2. Expand the Fields and Values group

  3. Double-click the field that you want to query (“TYPE_2”)

  4. Click All Unique in the panel that shows up on the right

  5. From the list, double-click ‘Borough’. In the Expression editor field, write the following query:

    "TYPE_2"  =  'Borough'
  6. Click Select Features

From the expression builder dialog, you can also use Function list ► Recent (Selection) to make a selection that you have used before. The dialog remembers the last 20 expressions used. See Expressões for more information and examples.


Save your selection into a new file

Users can save selected features into a New Temporary Scratch Layer or a New Vector Layer using Edit ► Copy Features and Edit ► Paste Features as in the desired format. Selecionar Feições Por Valor

This selection tool opens the layer’s feature form allowing the user to choose which value to look for for each field, whether the search should be case-sensitive, and the operation that should be used. The tool has also autocompletes, automatically filling the search box with existing values.


Fig. 11.20 Filter/Select features using form dialog

Alongside each field, there is a drop-down list with options to control the search behaviour:

Field search option




Exclude Field from the search




Equal to (=)




Not equal to (≠)




Greater than (>)



Less than (<)



Greater than or equal to (≥)



Less than or equal to (≤)



Between (inclusive)



Not between (inclusive)





Does not contain


Is missing (null)




Is not missing (not null)




Starts with


Ends with


For string comparisons, it is also possible to use the checkbox Case sensitive option.

After setting all search options, click Select features to select the matching features. The drop-down options are:

  • Selecionar feições

  • Add to current selection

  • Remove from current selection

  • Filtrar seleção atual

You can also clear all search options using the Reset form button.

Once the conditions are set, you can also either:

  • Zoom to features on the map canvas without the need of a preselection

  • Flash features, highlighting the matching features. This is a handy way to identify a feature without selection or using the Identify tool. Note that the flash does not alter the map canvas extent and would be visible only if the feature is within the bounds of the current map canvas.

11.5.2. Identifying Features

The Identify tool allows you to interact with the map canvas and get information on features in a pop-up window. To identify features, use:

  • Exbir ► Identificar Feições

  • Ctrl+Shift+I (or osx Cmd+Shift+I),

  • identify Identify Features icon on the Attributes toolbar Using the Identify Features tool

QGIS offers several ways to identify features with the identify Identify Features tool:

  • left click identifies features according to the selection mode and the selection mask set in the Identify Results panel

  • right click with Identify Feature(s) as selection mode set in the Identify Results panel fetches all snapped features from all visible layers. This opens a context menu, allowing the user to choose more precisely the features to identify or the action to execute on them.

  • right click with Identify Features by Polygon as selection mode in the Identify Results panel identifies the features that overlap with the chosen existing polygon, according to the selection mask set in the Identify Results panel


Filter the layers to query with the Identify Features tool

Under Layer Capabilities in Project ► Properties… ► Data Sources, uncheck the Identifiable column next to a layer to avoid it being queried when using the identify Identify Features tool in a mode other than Current Layer. This is a handy way to return features from only layers that are of interest for you.

If you click on feature(s), the Identify Results dialog will list information about the feature(s) clicked. The default view is a tree view in which the first item is the name of the layer and its children are its identified feature(s). Each feature is described by the name of a field along with its value. This field is the one set in Layer Properties ► Display. All the other information about the feature follows. Informações da feição

The Identify Results dialog can be customized to display custom fields, but by default it will display the following information:

  • The feature display name;

  • Actions: Actions can be added to the identify feature windows. The action is run by clicking on the action label. By default, only one action is added, namely View feature form for editing. You can define more actions in the layer’s properties dialog (see Propriedades de Ações).

  • Derived: This information is calculated or derived from other information. It includes:

    • general information about the feature’s geometry:

      • depending on the geometry type, the cartesian measurements of length, perimeter or area in the layer’s CRS units. For 3D line vectors the cartesian line length is available.

      • depending on the geometry type and if an ellipsoid is set in the project properties dialog for Measurements, the ellipsoidal values of length, perimeter or area using the specified units

      • the count of geometry parts in the feature and the number of the part clicked

      • the count of vertices in the feature

    • coordinate information, using the project properties Coordinates display settings:

      • X and Y coordinate values of the point clicked

      • the number of the closest vertex to the point clicked

      • X and Y coordinate values of the closest vertex (and Z/M if applicable)

      • se você clicar em um segmento curvo, o raio dessa seção também será mostrado.

  • Data attributes: This is the list of attribute fields and values for the feature that has been clicked.

  • information about the related child feature if you defined a relation:

    • the name of the relation

    • the entry in reference field, e.g. the name of the related child feature

    • Actions: lists actions defined in the layer’s properties dialog (see Propriedades de Ações) and the default action is View feature form.

    • Data attributes: This is the list of attributes fields and values of the related child feature.


Links in the feature’s attributes are clickable from the Identify Results panel and will open in your default web browser.


Fig. 11.21 Identify Results dialog The Identify Results dialog

At the top of the window, you have a handful of tools:

  • formView Open Form of the current feature

  • expandTree Expand tree

  • collapseTree Collapse tree

  • expandNewTree Expand New Results by Default to define whether the next identified feature’s information should be collapsed or expanded

  • deselectAll Clear Results

  • editCopy Copy selected feature to clipboard

  • filePrint Print selected HTML response

  • selection mode to use to fetch features to identify:

    • identifyByRectangle Identify Features by area or single click

    • identifyByPolygon Identify Features by Polygon

    • identifyByFreehand Identify Features by Freehand

    • identifyByRadius Identify Features by Radius


    When using identifyByPolygon Identify Features by Polygon, you can right-click any existing polygon and use it to identify overlapping features in another layer.

At the bottom of the window are the Mode and View combo boxes. Mode defines from which layers features should be identified:

  • Current layer: only features from the selected layer are identified. The layer need not be visible in the canvas.

  • Top down, stop at first: only features from the upper visible layer.

  • Top down: all features from the visible layers. The results are shown in the panel.

  • Layer selection: opens a context menu where the user selects the layer to identify features from, similar to a right-click. Only the chosen features will be shown in the result panel.

The View can be set as Tree, Table or Graph. ‘Table’ and ‘Graph’ views can only be set for raster layers.

The identify tool allows you to checkbox Auto open form for single feature results, found under options Identify Settings. If checked, each time a single feature is identified, a form opens showing its attributes. This is a handy way to quickly edit a feature’s attributes.

Outras funções podem ser encontrados no menu de contexto do item identificado. Por exemplo, do menu de contexto, você pode:

  • Ver o formulário da feição

  • Zoom para feição

  • Copiar feição: Copiar todos os atributos e a geometria da feição

  • Toggle feature selection: Add identified feature to selection

  • Copiar o valor do atributo: Copiar apenas o valor do atributo que clicou.

  • Copy feature attributes: Copy the attributes of the feature

  • Limpar resultados: apaga os resultados na janela

  • Limpar destaques: Remover feiçõesdestacadas no mapa

  • Destaque todos

  • Destaque a camada

  • Ativar camada: escolha uma camada a ser ativada

  • Propriedades da camada: Abre a janela de propriedades da camada

  • Estender tudo

  • Encolher tudo

11.6. Salvar e Compartilhar Propriedades da Camada

11.6.1. Managing Custom Styles

When a vector layer is added to the map canvas, QGIS by default uses a random symbol/color to render its features. However, you can set a default symbol in Project ► Properties… ► Default styles that will be applied to each newly added layer according to its geometry type.

Most of the time, though, you’d rather have a custom and more complex style that can be applied automatically or manually to the layers (with less effort). You can achieve this by using the Style menu at the bottom of the Layer Properties dialog. This menu provides you with functions to create, load and manage styles.

A style stores any information set in the layer properties dialog to render or interact with the layer (including symbology, labeling, fields and form definitions, actions, diagrams…) for vector layers, or the pixels (band or color rendering, transparency, pyramids, histogram …) for raster.


Fig. 11.22 Vector layer style combo box options

By default, the style applied to a loaded layer is named default. Once you have got the ideal and appropriate rendering for your layer, you can save it by clicking the selectString Style combo box and choosing:

  • Rename Current: The active style is renamed and updated with the current options

  • Add: A new style is created using the current options. By default, it will be saved in the QGIS project file. See below to save the style in another file or a database

  • Remove: Delete unwanted style, in case you have more than one style defined for the layer.

At the bottom of the Style drop-down list, you can see the styles set for the layer with the active one checked.

Note that each time you validate the layer properties dialog, the active style is updated with the changes you’ve made.

You can create as many styles as you wish for a layer but only one can be active at a time. In combination with Map Themes, this offers a quick and powerful way to manage complex projects without the need to duplicate any layer in the map legend.


Given that whenever you apply modifications to the layer properties, changes are stored in the active style, always ensure you are editing the right style to avoid mistakenly altering a style used in a map theme.


Manage styles from layer context menu

Right-click on the layer in the Layers panel to copy, paste, add or rename layer styles.

11.6.2. Storing Styles in a File or a Database

While styles created from the Style combo box are by default saved inside the project and can be copied and pasted from layer to layer in the project, it’s also possible to save them outside the project so that they can be loaded in another project. Save as text file

Clicking the selectString Style ► Save Style, you can save the style as a:

  • QGIS layer style file (.qml)

  • SLD file (.sld), only available for vector layers

Used on file-based format layers (.shp, .tab…), Save as Default generates a .qml file for the layer (with the same name). SLDs can be exported from any type of renderer – single symbol, categorized, graduated or rule-based – but when importing an SLD, either a single symbol or rule-based renderer is created. This means that categorized or graduated styles are converted to rule-based. If you want to preserve those renderers, you have to use the QML format. On the other hand, it can be very handy sometimes to have this easy way of converting styles to rule-based. Save in database

Vector layer styles can also be stored in a database if the layer datasource is a database provider. Supported formats are PostGIS, GeoPackage, SpatiaLite, MSSQL and Oracle. The layer style is saved inside a table (named layer_styles) in the database. Click on Save Style… ► Save in database then fill in the dialog to define a style name, add a description, a .ui file if applicable and to check if the style should be the default style.

You can save several styles for a single table in the database. However, each table can have only one default style. Default styles can be saved in the layer database or in qgis.db, a local SQLite database in the active user profile directory.


Fig. 11.23 Save Style in database Dialog


Sharing style files between databases

You can only save your style in a database if the layer comes from such a database. You can’t mix databases (layer in Oracle and style in MSSQL for instance). Use instead a plain text file if you want the style to be shared among databases.


You may encounter issues restoring the layer_styles table from a PostgreSQL database backup. Follow QGIS layer_style table and database backup to fix that. Load style

When loading a layer in QGIS, if a default style already exists for this layer, QGIS loads the layer with this style. Also Style ► Restore Default looks for and loads that file, replacing the layer’s current style.

Style ► Load Style helps you apply any saved style to a layer. While text-file styles (.sld or .qml) can be applied to any layer whatever its format, loading styles stored in a database is only possible if the layer is from the same database or the style is stored in the QGIS local database.

The Database Styles Manager dialog displays a list of styles related to the layer found in the database and all the other styles saved in it, with name and description.


Quickly share a layer style within the project

You can also share layer styles within a project without importing a file or database style: right-click on the layer in the Layers Panel and, from the Styles combo box , copy the style of a layer and paste it to a group or a selection of layers: the style is applied to all the layers that are of the same type (vector vs raster) as the original layer and, in the case of vector layers, have the same geometry type (point, line or polygon).

11.6.3. Layer definition file

Layer definitions can be saved as a Layer Definition File (.qlr) using Export ► Save As Layer Definition File… in the active layers’ context menu. A layer definition file (.qlr) includes references to the data source of the layers and their styles. .qlr files are shown in the Browser Panel and can be used to add the layers (with the saved style) to the Layers Panel. You can also drag and drop .qlr files from the system file manager into the map canvas.

11.7. Storing values in Variables

In QGIS, you can use variables to store useful recurrent values (e.g. the project’s title, or the user’s full name) that can be used in expressions. Variables can be defined at the application’s global level, project level, layer level, layout level, and layout item’s level. Just like CSS cascading rules, variables can be overwritten - e.g., a project level variable will overwrite any application global level variables set with the same name. You can use these variables to build text strings or other custom expressions using the @ character before the variable name. For example in print layout creating a label with this content:

This map was made using QGIS [% @qgis_version %]. The project file for this
map is: [% @project_path %]

Will render the label like this:

This map was made using QGIS 3.4.4-Madeira. The project file for this map is:

Besides the preset read-only variables, you can define your own custom variables for any of the levels mentioned above. You can manage:

To differentiate from editable variables, read-only variable names and values are displayed in italic. On the other hand, higher level variables overwritten by lower level ones are strike through.


Fig. 11.24 Variables editor at the project level


You can read more about variables and find some examples in Nyall Dawson’s Exploring variables in QGIS 2.12, part 1, part 2 and part 3 blog posts.

11.8. Autenticação

QGIS has the facility to store/retrieve authentication credentials in a secure manner. Users can securely save credentials into authentication configurations, which are stored in a portable database, can be applied to server or database connections, and are safely referenced by their ID tokens in project or settings files. For more information see Sistema de Autenticação.

A master password needs to be set up when initializing the authentication system and its portable database.

11.9. Common widgets

In QGIS, there are some options you’ll often have to work with. For convenience, QGIS provides you with special widgets that are presented below.

11.9.1. Color Selector The color dialog

A caixa de diálogo Selecionar Cor aparecerá sempre que você clicar no ícone selectColor para escolher uma cor. Os recursos desta caixa de diálogo dependem do estado da caixa de seleção do parâmetro Usar caixas de diálogo do seletor de cores nativas em Configurações ► Opções…► Geral. Quando marcada, a caixa de diálogo colorida usada é a nativa do SO no qual o QGIS está sendo executado. Caso contrário, o seletor de cores personalizado QGIS é usado.

The custom color chooser dialog has four different tabs which allow you to select colors by colorBox Color ramp, colorWheel Color wheel, colorSwatches Color swatches or colorPicker Color picker. With the first two tabs, you can browse to all possible color combinations and apply your choice to the item.


Fig. 11.25 Color selector ramp tab

In the colorSwatches Color swatches tab, you can choose from a list of color palettes (see Colors Settings for details). All but the Recent colors palette can be modified with the signPlus Add current color and signMinus Remove selected color buttons at the bottom of the frame.

The button next to the palette combo box also offers several options to:

  • copiar, colar, importar ou exportar cores

  • create, import or remove color palettes

  • add the custom palette to the color selector widget with the Show in Color Buttons item (see Fig. 11.27)


Fig. 11.26 Color selector swatches tab

Another option is to use the colorPicker Color picker which allows you to sample a color from under your mouse cursor at any part of the QGIS UI or even from another application: press the space bar while the tab is active, move the mouse over the desired color and click on it or press the space bar again. You can also click the Sample Color button to activate the picker.

Whatever method you use, the selected color is always described through color sliders for HSV (Hue, Saturation, Value) and RGB (Red, Green, Blue) values. The color is also identifiable in HTML notation.

Modifying a color is as simple as clicking on the color wheel or ramp or on any of the color parameters sliders. You can adjust such parameters with the spinbox beside or by scrolling the mouse wheel over the corresponding slider. You can also type the color in HTML notation. Finally, there is an Opacity slider to set transparency level.

The dialog also provides a visual comparison between the Old color (applied to object) and the Current one (being selected). Using drag-and-drop or pressing the atlasNext Add color to swatch button, any of these colors can be saved in a slot for easy access.


Quick color modification

Drag-and-drop a color selector widget onto another one to apply its color. The color drop-down shortcut

Click the drop-down arrow to the right of the selectColor color button to display a widget for quick color selection. This shortcut provides access to:

  • a color wheel to pick a color from

  • an alpha slider to change color opacity

  • the color palettes previously set to Show in Color Buttons

  • copy the current color and paste it into another widget

  • pick a color from anywhere on your computer display

  • choose a color from the color selector dialog

  • drag-and-drop the color from one widget to another for quick modification


When the color widget is set to a project color through the data-defined override properties, the above functions for changing the color are unavailable. You’d first need to Unlink color or Clear the definition.


Fig. 11.27 Quick color selector menu The color ramp drop-down shortcut

Color ramps are a practical way to apply a set of colors to one or many features. Their creation is described in the Setting a Color Ramp section. As for the colors, pressing the selectColorRamp color ramp button opens the corresponding color ramp type dialog allowing you to change its properties.


Fig. 11.28 Customizing a colorbrewer ramp

The drop-down menu to the right of the button gives quick access to a wider set of color ramps and options:

  • Invert Color Ramp

  • a preview of the gradient or catalog: cpt-city color ramps flagged as Favorites in the Style Manager dialog

  • All Color Ramps to access the compatible color ramps database

  • Create New Color Ramp… of any supported type that could be used in the current widget (note that this color ramp will not be available elsewhere unless you save it in the library)

  • Edit Color Ramp…, the same as clicking the whole color ramp button

  • Save Color Ramp…, to save the current color ramp with its customizations in the style library


Fig. 11.29 Quick color ramp selection widget

11.9.2. Symbol Widget

The Symbol selector widget is a convenient shortcut when you want to set symbol properties of a feature. Clicking the drop-down arrow shows the following symbol options, together with the features of the color drop-down widget:

  • Configure Symbol…: the same as pressing the symbol selector widget. It opens a dialog to set the symbol parameters.

  • Copiar Símbolo do item atual

  • Paste Symbol to the current item, speeding configuration

11.9.3. Font Selector

The Font selector widget is a convenient shortcut when you want to set font properties for textual information (feature labels, decoration labels, map legend text, …). Clicking the drop-down arrow shows some or all of the following options:


Fig. 11.30 Font selector drop-down menu

  • Font Size in the associated unit

  • Recent Fonts ► menu with the active font checked (at the top)

  • Configure Format…: same as pressing the font selector widget. It opens a dialog to set text format parameters. Depending on the context, it can be the OS default Text format dialog or the QGIS custom dialog with advanced formatting options (opacity, orientation, buffer, background, shadow, …) as described in section Formatting the label text.

  • Copy Format of the text

  • Paste Format to the text, speeding configuration

  • the color widget for quick color setting

11.9.4. Unit Selector

Size properties of the items (labels, symbols, layout elements, …) in QGIS are not necessarily bound to either the project units or the units of a particular layer. For a large set of properties, the Unit selector drop-down menu allows you to tweak their values according to the rendering you want (based on screen resolution, paper size, or the terrain). Available units are:

  • Millimeters

  • Pontos

  • Pixels

  • Polegadas

  • Meters at Scale: This allows you to always set the size in meters, regardless of what the underlying map units are (e.g. they can be in inches, feet, geographic degrees, …). The size in meters is calculated based on the current project ellipsoid setting and a projection of the distances in meters at the center of the current map extent.

  • and Map Units: The size is scaled according to the map view scale. Because this can lead to too big or too small values, use the options button next to the entry to constrain the size to a range of values based on:

    • The Minimum scale and the Maximum scale: The value is scaled based on the map view scale until you reach any of these scale limits. Out of the range of scale, the value at the nearest scale limit is kept.

    • and/or The Minimum size and the Maximum size in mm: The value is scaled based on the map view scale until it reaches any of these limits; Then the limit size is kept.


    Fig. 11.31 Adjust scaling range dialog

11.9.5. Number Formatting

Numeric formatters allow formatting of numeric values for display, using a variety of different formatting techniques (for instance scientific notation, currency values, percentage values, etc). One use of this is to set text in a layout scale bar or fixed table.

Different categories of formats are supported. For most of them, you can set part or all of the following numeric options:

  • checkbox Show thousands separator

  • unchecked Show plus sign

  • unchecked Show trailing zeros

But they can also have their custom settings. Provided categories are:

  • General, the default category: has no setting and displays values as set in the parent widget properties or using the global settings.

  • Number

    • The value can be Round to a self defined number of Decimal places or their Significant figures

    • customize the Thousands separator and Decimal separator

  • Bearing for a text representation of a direction/bearing using:

    • Format: possible ranges of values are 0 to 180°, with E/W suffix, -180 to +180° and 0 to 360°

    • number of Decimal places

  • Currency for a text representation of a currency value.

    • Prefix

    • Suffix

    • number of Decimal places

  • Fraction for a vulgar fractional representation of a decimal value (e.g. 1/2 instead of 0.5)

    • unchecked Use unicode super/subscript to show. For example 1/2 instead of 1/2

    • unchecked Use dedicated Unicode characters

    • customize the Thousands separator

  • Percentage - appends % to the values, with setting of:

    • number of Decimal places

    • Scaling to indicate whether the actual values already represent percentages (then they will be kept as is) or fractions (then they are converted)

  • Scientific notation in the form 2.56e+03. The number of Decimal places can be set.

A live preview of the settings is displayed under the Sample section.

11.9.6. Modos de Mistura

QGIS offers different options for special rendering effects with these tools that you may previously only know from graphics programs. Blending modes can be applied on layers and features, and also on print layout items:

  • ** Normal **: Esse é o modo de mescla padrão, que usa o canal alfa do pixel superior para combinar com o pixel abaixo dele. As cores não são misturadas.

  • Lighten: This selects the maximum of each component from the foreground and background pixels. Be aware that the results tend to be jagged and harsh.

  • Screen: Light pixels from the source are painted over the destination, while dark pixels are not. This mode is most useful for mixing the texture of one item with another item (such as using a hillshade to texture another layer).

  • Dodge: Brighten and saturate underlying pixels based on the lightness of the top pixel. Brighter top pixels cause the saturation and brightness of the underlying pixels to increase. This works best if the top pixels aren’t too bright. Otherwise the effect is too extreme.

  • Addition: Adds pixel values of one item to the other. In case of values above the maximum value (in the case of RGB), white is displayed. This mode is suitable for highlighting features.

  • Darken: Retains the lowest values of each component of the foreground and background pixels. Like lighten, the results tend to be jagged and harsh.

  • Multiply: Pixel values of the top item are multiplied with the corresponding values for the bottom item. The results are darker.

  • Burn: Darker colors in the top item cause the underlying items to darken. Burn can be used to tweak and colorize underlying layers.

  • Overlay: Combines multiply and screen blending modes. Light parts become lighter and dark parts become darker.

  • Soft light: Very similar to overlay, but instead of using multiply/screen it uses color burn/dodge. This is supposed to emulate shining a soft light onto an image.

  • Hard light: Hard light is also very similar to the overlay mode. It’s supposed to emulate projecting a very intense light onto an image.

  • Difference: Subtracts the top pixel from the bottom pixel, or the other way around, in order always to get a positive value. Blending with black produces no change, as the difference with all colors is zero.

  • Subtract: Subtracts pixel values of one item from the other. In the case of negative values, black is displayed.

11.9.7. Data defined override setup

Next to many options in the vector layer properties dialog or settings in the print layout, you will find a dataDefined Data defined override icon. Using expressions based on layer attributes or item settings, prebuilt or custom functions and variables, this tool allows you to set dynamic values for parameters. When enabled, the value returned by this widget is applied to the parameter regardless of its normal value (checkbox, textbox, slider…). The data defined override widget

Clicking the dataDefined Data defined override icon shows the following entries:

  • Description… that indicates if the option is enabled, which input is expected, the valid input type and the current definition. Hovering over the widget also pops up this information.

  • Store data in the project: a button allowing the property to be stored using to the Propriedades de armazenamento auxiliar mechanism.

  • Field type: an entry to select from the layer’s fields that match the valid input type.

  • Color: when the widget is linked to a color property, this menu gives access to the colors defined as part of the current project’s colors scheme.

  • Variable: a menu to access the available user-defined variables

  • Edit… button to create or edit the expression to apply, using the Expression String Builder dialog. To help you correctly fill in the expression, a reminder of the expected output’s format is provided in the dialog.

  • botões Colar e Copiar.

  • Clear button to remove the setup.

  • For numeric and color properties, Assistant… to rescale how the feature data is applied to the property (more details below)


Use right-click to (de)activate the data override

When the data-defined override option is set up correctly the icon is yellow dataDefineOn or dataDefineExpressionOn. If it is broken, the icon is red dataDefineError or dataDefineExpressionError.

You can enable or disable a configured dataDefined data-defined override button by simply clicking the widget with the right mouse button. Using the data-defined assistant interface

When the dataDefined Data-defined override button is associated with a numeric or color parameter, it has an Assistant… option that allows you to change how the data is applied to the parameter for each feature. The assistant allows you to:

  • Define the Input data, ie:

    • the attribute to represent, using the Field listbox or the expression Set column expression function (see Expressões)

    • the range of values to represent: you can manually enter the values or use the refresh Fetch value range from layer button to fill these fields automatically with the minimum and maximum values returned by the chosen attribute or the expression applied to your data

  • unchecked Apply transform curve: by default, output values (see below for setting) are applied to input features following a linear scale. You can override this logic: enable the transform option, click on the graphic to add break point(s) and drag the point(s) to apply a custom distribution.

  • Define the Output values: the options vary according to the parameter to define. You can globally set:

    • the minimum and maximum values to apply to the selected property (n case of a color setting, you’ll need to provide a color ramp)

    • the Scale method of representation which can be Flannery, Exponential, Surface or Radius

    • the Exponent to use for data scaling

    • the output value or color to represent features with NULL values

When compatible with the property, a live-update preview is displayed in the right-hand side of the dialog to help you control the value scaling.


Fig. 11.32 The data-defined size assistant

The values presented in the varying size assistant above will set the size ‘Data-defined override’ with:

coalesce(scale_exp(Importance, 1, 20, 2, 10, 0.57), 1)