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Interace do QGIS

When QGIS starts, you are presented with the GUI as shown in the figure (the numbers 1 through 5 in yellow circles are discussed below).

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Interface QGIS com a amostra de dados do Alaska

Note

As decorações na sua janela (Barra de Títulos, etc.) podem aparecer diferente maneira dependendo do seu sistema operativo e gestor de janelas.

A interface do QGIS está dividida em cinco componentes:

  1. Barra de Menus

  2. Barras de Ferramentas

  3. Painéis

  4. Vista do Mapa

  5. Barra de Estado

These five components of the QGIS interface are described in more detail in the following sections. Two more sections present keyboard shortcuts and context help.

Painéis e Barras de Ferramentas

From the View menu (or kde Settings), you can switch on and off QGIS widgets (Panels ‣) or toolbars (Toolbars ‣). You can (de)activate any of them by right-clicking the menu bar or a toolbar and choose the item you want. Each panel or toolbar can be moved and placed wherever you feel comfortable within QGIS interface. The list can also be extended with the activation of Core or external plugins.

Barras de Ferramentas

The toolbar provides access to most of the same functions as the menus, plus additional tools for interacting with the map. Each toolbar item has pop-up help available. Hold your mouse over the item and a short description of the tool’s purpose will be displayed.

Every toolbar can be moved around according to your needs. Additionally, they can be switched off using the right mouse button context menu, or by holding the mouse over the toolbars.

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O menu da Barra de Ferramentas

Tip

Restaurar as Barras de Ferramentas

If you have accidentally hidden a toolbar, you can get it back by choosing menu option View ‣ Toolbars ‣ (or kde Settings ‣ Toolbars ‣). If for some reason a toolbar (or any other widget) totally disappears from the interface, you’ll find tips to get it back at restoring initial GUI.

Painéis

Besides toolbars, QGIS provides by default many panels to work with. Panels are special widgets that you can interact with (selecting options, checking boxes, filling values...) in order to perform a more complex task.

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O Menu de Painéis

Em baixo estão listados painéis pré-definidos fornecidos pelo QGIS:

Vista do Mapa

Also called Map canvas, this is the “business end” of QGIS — maps are displayed in this area. The map displayed in this window will depend on the vector and raster layers you have chosen to load.

When you add a layer (see e.g. Opening Data), QGIS automatically looks for its Coordinate Reference System (CRS) and zooms to its extent if you work in a blank QGIS project. The layer’s CRS is then applied to the project. If there are already layers in the project, and in the case the new layer has the same CRS as the project, its features falling in the current map canvas extent will be visualized. If the new layer is in a different CRS from the project’s, you must Enable on-the-fly CRS transformation from the Project ‣ Project Properties ‣ CRS (see Define On The Fly (OTF) CRS Transformation). The added layer should now be visible if data are available in the current view extent.

The map view can be panned, shifting the focus of the map display to another region, and it can be zoomed in and out. Various other operations can be performed on the map as described in the Barras de Ferramentas description. The map view and the legend are tightly bound to each other — the maps in view reflect changes you make in the legend area.

Tip

Aumentado o Mapa com a roda do Rato

Pode usar a roda do rato para ampliar ou afastar o mapa. Posicione o cursos do rato dentro da área do mapa e rode a roda para a frente (longe de si) para ampliar e para trás (perto de si) para afastar. A posição do cursor do mapa é centrada onde a ampliação ocorre. Pode personalizar o comportamento de ampliação da roda do rato usando o separador Ferramentas de mapa no menu Configurações ‣ Opções .

Tip

Movendo o Mapa com as Setas de Direcção e Barra de Espaço

You can use the arrow keys to pan the map. Place the mouse cursor inside the map area and click on the right arrow key to pan east, left arrow key to pan west, up arrow key to pan north and down arrow key to pan south. You can also pan the map using the space bar or the click on mouse wheel: just move the mouse while holding down space bar or click on mouse wheel.

Barra de Estado

The status bar provides you with general information about the map view, and actions processed or available and offers you tools to manage the map view.

On the left side of the status bar, you can get a summary of actions you’ve done (such as selecting features in a layer, removing layer) or a long description of the tool you are hovering over (not available for all tools). On startup, the bar status also informs you about availability of new or upgradeable plugins (if checked in Plugin Manager settings).

In case of lengthy operations, such as gathering of statistics in raster layers or rendering several layers in map view, a progress bar is displayed in the status bar to show the current progress of the action.

The tracking Coordinate option shows the current position of the mouse, following it while moving across the map view. You can set the unit (and precision) to use in the project properties, General tab. Click on the small button at the left of the textbox to toggle between the Coordinate option and the extents Extents option that displays in map units, the coordinates of the current lower leftmost and upper rightmost points of the map view, as you pan and zoom in and out.

Next to the coordinate display you will find the Scale display. It shows the scale of the map view. If you zoom in or out, QGIS shows you the current scale. There is a scale selector, which allows you to choose among predefined and custom scales to assign to the map view.

On the right side of the scale display you can define a current magnification level for your map view. This allows to zoom in to a map without altering the map scale, making it easier to accurately tweak the positions of labels and symbols. The magnification level is expressed as a percentage. If the Magnifier has a level of 100%, then the current map is not magnified. Additionally, a default magnification value can be defined within Settings ‣ Options ‣ Rendering ‣ Rendering behaviour, which is very useful for high resolution screen to avoid too small symbols.

To the right of the magnifier tool you can define a current clockwise rotation for your map view in degrees.

On the right side of the status bar, there is a small checkbox which can be used to temporarily prevent layers being rendered to the map view (see section Renderização).

To the right of the render functions, you find the projectionDisabled Current CRS: icon with the EPSG code of the current project CRS. Clicking on this lets you Enable ‘on the fly’ CRS transformation properties for the current project and apply another CRS to the map view.

Finally, the messageLog Messages button opens the Log Messages Panel which informs you on underlying process (QGIS startup, plugins loading, processing tools...)

Tip

Calculando a Escala Correcta para o Seu Enquadramento do Mapa

When you start QGIS, the default CRS is WGS 84 (epsg 4326) and units are degrees. This means that QGIS will interpret any coordinate in your layer as specified in degrees. To get correct scale values, you can either manually change this setting, e.g. to meters, in the General tab under Project ‣ Project Properties, or you can use the projectionDisabled Current CRS: icon seen above. In the latter case, the units are set to what the project projection specifies (e.g., +units=us-ft).

Note that CRS choice on startup can be set in Settings ‣ Options ‣ CRS.