.. only:: html .. index:: Vector, OGR, Raster, GDAL, Data, Format .. index:: PostGreSQL, PostGIS, GeoPackage, SpatiaLite, GRASS, DXF .. index:: ArcInfo Binary Grid, ArcInfo ASCII Grid, GeoTIFF, Erdas Imagine .. _opening_data: ************** Opening Data ************** .. only:: html .. contents:: :local: As part of an Open Source Software ecosystem, QGIS is built upon different libraries that, combined with its own providers, offer capabilities to read and often write a lot of formats: * Vector data formats include ESRI formats (Shapefile, Geodatabase...), MapInfo and MicroStation file formats, AutoCAD DWG/DXF, GeoPackage, GeoJSON, GRASS, GPX, KML, Comma Separated Values, and many more... Read the complete list of `OGR vector supported formats `_. * Raster data formats include ArcInfo Binary Grid, ArcInfo ASCII Grid, JPEG, GeoTIFF, ERDAS IMAGINE, MBTiles, R or Idrisi rasters, ASCII Gridded XYZ, GDAL Virtual, SRTM, Sentinel Data, and many more... Read the complete list of `raster supported formats `_. * Database formats include PostgreSQL/PostGIS, SQLite/SpatiaLite, Oracle, DB2 or MSSQL Spatial, MySQL... * Support of web data services (WM(T)S, WFS, WCS, CSW, ArcGIS Servers...) is also handled by QGIS providers (see :ref:`working_with_ogc`). * You can also read supported files from archived folders and use QGIS native formats such as virtual and memory layers. As of the date of this document, more than 80 vector and 140 raster formats are supported by the `GDAL/OGR `_ and QGIS native providers. .. note:: Not all of the listed formats may work in QGIS for various reasons. For example, some require external proprietary libraries, or the GDAL/OGR installation of your OS may not have been built to support the format you want to use. To see the list of available formats, run the command line ``ogrinfo --formats`` (for vector) and ``gdalinfo --formats`` (for raster), or check :menuselection:`Settings --> Options --> GDAL` menu (for raster) in QGIS. .. let's use ogrinfo until a list of vector formats is provided in a (GDAL/)OGR tab .. _datasourcemanager: In QGIS, depending on the data format, there are different tools to open it, mainly available in the :menuselection:`Layer --> Add Layer -->` menu or from the :guilabel:`Manage Layers` toolbar (enabled through :menuselection:`View --> Toolbars` menu). However, all these tools point to a unique dialog, the :guilabel:`Data Source Manager` dialog that you can directly open with the |dataSourceManager| :sup:`Open Data Source Manager` button available on the :guilabel:`Data Source Manager Toolbar` or by pressing :kbd:`Ctrl+L`. Indeed, the :guilabel:`Data Source Manager` dialog offers a unified interface to open vector or raster file-based data as well as databases or web services supported by QGIS. It can be set modal or not with the |checkbox| :guilabel:`Modeless data source manager dialog` in :menuselection:`Settings --> Options --> General` menu. .. _figure_datasource_manager: .. figure:: img/datasource_manager.png :align: center QGIS Data Source Manager dialog Beside this main entry point, you also have the |dbManager| :guilabel:`DB Manager` plugin that offers advanced capabilities to analyze and manipulate connected databases. More information on DB Manager capabilities are exposed in :ref:`dbmanager`. There are also many other tools, native or third-party plugins, that help you open dedicated data formats. This chapter will describe only the tools provided by default in QGIS to load data. It will mainly focus on the :guilabel:`Data Source Manager` dialog but more than describing each tab, it will also explore the tools based on the data provider or format specificities. .. index:: Browse data, Add layers .. _browser_panel: The Browser Panel ================= The :guilabel:`Browser` is one of the main ways to quickly and easily add your data to projects. It's available as: * a :guilabel:`Data Source Manager` tab, enabled pressing the |dataSourceManager| :sup:`Open Data Source Manager` button (:kbd:`Ctrl+L`); * as a QGIS panel you can open from the menu :menuselection:`View --> Panels` (or |kde| :menuselection:`Settings --> Panels`) or by pressing :kbd:`Ctrl+2`. In both cases, the :guilabel:`Browser` helps you navigate in your file system and manage geodata, regardless the type of layer (raster, vector, table), or the datasource format (plain or compressed files, database, web services). The context menu for an element in the :guilabel:`Browser` panel is opened by right-clicking on it. For file system directory entries, the context menu offers the following: * :guilabel:`Add as a Favorite` * :guilabel:`Properties...` * :guilabel:`Hide from Browser` * :guilabel:`Fast Scan this Directory` * :guilabel:`New Directory...` * :guilabel:`Open Directory` :guilabel:`Favourites`, can also be removed and renamed: * :guilabel:`Rename favourite...` * :guilabel:`Remove favourite` For leaf entries that can act as layers in the project, the context menu will have a selection of entries. For example, for non-database, non-service-based vector, raster and mesh data sources: * :guilabel:`Add Selected Layer(s) to Canvas` * :guilabel:`Properties...` * :guilabel:`Delete File ""...` In the :guilabel:`Layer properties` entry, you will find (similar to what you will find in the :ref:`vector ` and :ref:`raster ` layer properties once the layers have been added to the project): * :guilabel:`Metadata` for the layer. Metadata groups: :guilabel:`Information from provider` (if possible, :guilabel:`Path` will be a hyperlink to the source), :guilabel:`Identification`, :guilabel:`Extent`, :guilabel:`Access`, :guilabel:`Fields` (for vector layers), :guilabel:`Bands` (for raster layers), :guilabel:`Contacts`, :guilabel:`Links` (for vector layers), :guilabel:`References` (for raster layers), :guilabel:`History`. * A :guilabel:`Preview` panel * The attribute table for vector sources (in the :guilabel:`Attributes` panel). To add a layer to the project using the :guilabel:`Browser`: #. Enable the :guilabel:`Browser` as described above. A browser tree with your file system, databases and web services is displayed. You may need to connect databases and web services before they appear (see dedicated sections). #. Find the layer in the list. #. Use the context menu, double-click its name, or drag-and-drop it into the :ref:`map canvas `. Your layer is now added to the :ref:`Layers panel ` and can be viewed on the map canvas. .. tip:: **Open a QGIS project directly from the browser** You can also open a QGIS project directly from the Browser panel by double-clicking its name or by drag-and-drop into the map canvas. Once a file is loaded, you can zoom around it using the map navigation tools. To change the style of a layer, open the :guilabel:`Layer Properties` dialog by double clicking on the layer name or by right-clicking on the name in the legend and choosing :menuselection:`Properties` from the context menu. See section :ref:`vector_style_menu` for more information on setting symbology of vector layers. At the top of the Browser panel, you find some icons that help you to: * |addLayer| :sup:`Add Selected Layers`: you can also add data into the map canvas by selecting **Add selected layer(s)** from the layer's context menu; * |draw| :sup:`Refresh` the browser tree; * |filterMap| :sup:`Filter Browser` to search for specific data. Enter a search word or wildcard and the browser will filter the tree to only show paths to matching DB tables, filenames or folders -- other data or folders won't be displayed. See the Browser Panel(2) example on the figure_browser_panels_. The comparison can be case-sensitive or not. It can also be set to: * **normal**: return any item containing the search text; * using **wildcard(s)**: fine tune the search using ``?`` and/or ``*`` characters to specify the position of the search text; * using a **regular expression**. * |collapseTree| :sup:`Collapse All` the whole tree; * |metadata| :sup:`Enable/disable properties widget`: when toggled on, a new widget is added at the bottom of the panel showing, if applicable, metadatas of the selected item. Right-click an item in the browser tree helps you to: * in case of file or table, display its metadata or open it in your project. Tables can even be renamed, deleted or truncated; * in case of folder, bookmark it into your favourites, hide it from the browser tree. Hidden folders can be managed from the :menuselection:`Settings --> Options --> Data Sources` tab; * create connection to databases or web servers; * refresh, rename or delete schema. You can also import files into databases or copy tables from one schema/database to another one with a simple drag-and-drop. There is a second browser panel available to avoid long scrolling while dragging. Just select the file and drag-and-drop from one panel to the other. .. _figure_browser_panels: .. figure:: img/browser_panels.png :align: center QGIS Browser panels side-by-side .. tip:: **Add layers to QGIS by simple drag-and-drop from your OS file browser** You can also add file(s) to the project by drag-and-dropping them from your operating system file browser to the :guilabel:`Layers Panel` or the map canvas. .. index:: DB Manager The DB Manager ============== The :guilabel:`DB Manager` Plugin is another one of the main and native tools to integrate and manage spatial database formats supported by QGIS (PostGIS, SpatiaLite, GeoPackage, Oracle Spatial, MSSQL, DB2, Virtual layers) in one user interface. It can be activated from the :menuselection:`Plugins --> Manage and Install Plugins...` menu. The |dbManager| :sup:`DB Manager` Plugin provides several features: * connect to databases and display its structure and contents; * preview tables of databases; * add layers to map canvas, either by double-click or drag-and-drop; * add layers to a database from the QGIS Browser or from another database; * create and add output of SQL queries to the map canvas; * create :ref:`virtual layers `. More information on DB Manager capabilities are exposed in :ref:`dbmanager`. .. _figure_db_manager_bis: .. figure:: img/db_manager.png :align: center DB Manager dialog Provider-based loading tools ============================= Beside Browser Panel and DB Manager, the main tools provided by QGIS to add layers regardless the format, you'll also find tools that are specific to data providers. .. note:: Some :ref:`external plugins ` also propose tools to open specific format files in QGIS. .. index:: Loading vector, Loading raster .. index:: ODBC, OGDI, Esri Personal Geodatabase, MySQL .. _loading_file: Loading a layer from a file --------------------------- To load a layer from a file, you can: * for vector data (like Shapefile, Mapinfo or dxf layer), click on |addOgrLayer| :sup:`Add Vector Layer` toolbar button, select the :menuselection:`Layer --> Add Layer -->` |addOgrLayer|:guilabel:`Add Vector Layer` menu option or press :kbd:`Ctrl+Shift+V`. This will bring up a new window (see figure_vector_add_) from which you can check |radioButtonOn| :guilabel:`File` and click on :guilabel:`Browse`. You can also specify the encoding for the file if desired. .. _figure_vector_add: .. figure:: img/addvectorlayerdialog.png :align: center Add Vector Layer Dialog * for raster layers, click on the |addRasterLayer| :sup:`Add Raster Layer` icon, select the :menuselection:`Layer --> Add Layer -->` |addRasterLayer| :guilabel:`Add Raster Layer` menu option or type :kbd:`Ctrl+Shift+R`. That will bring up a standard open file dialog (see figure_vector_open_), which allows you to navigate the file system and load a shapefile, a geotiff or other supported data source. The selection box :guilabel:`Filter` |selectString| allows you to preselect some supported file formats. Only the formats that have been well tested appear in the list. Other untested formats can be loaded by selecting ``All files (*.*)``. .. _figure_vector_open: .. figure:: img/shapefileopendialog.png :align: center Open an OGR Supported Vector Layer Dialog Selecting a file from the list and clicking :guilabel:`Open` loads it into QGIS. More than one layer can be loaded at the same time by holding down the :kbd:`Ctrl` or :kbd:`Shift` key and clicking on multiple items in the dialog. Figure_vector_loaded_ shows QGIS after loading the :file:`alaska.shp` file. .. _figure_vector_loaded: .. figure:: img/shapefileloaded.png :align: center QGIS with Shapefile of Alaska loaded .. note:: Because some formats like MapInfo (e.g., :file:`.tab`) or Autocad (:file:`.dxf`) allow mixing different types of geometry in a single file, loading such format in QGIS opens a dialog to select geometries to use in order to have one geometry per layer. .. index:: ArcInfo Binary Coverage, Tiger Format, UK National Transfer Format .. index:: US Census Bureau Using the |addOgrLayer| :sup:`Add Vector Layer` tool: * You can also load specific formats like ``ArcInfo Binary Coverage``, ``UK. National Transfer Format``, as well as the raw TIGER format of the ``US Census Bureau`` or ``OpenfileGDB``. To do that, you'd need to select |radioButtonOn| :guilabel:`Directory` as :guilabel:`Source type`. In this case a directory can be selected in the dialog after pressing :guilabel:`Browse`. * With the |radioButtonOn| :guilabel:`Database` source type you can select an existing database connection or create one to the selected database type. Available database types are ``ODBC``, ``OGDI Vectors``, ``Esri Personal Geodatabase``, ``MySQL`` as well as ``PostgreSQL`` or ``MSSQL``. Pressing the :guilabel:`New` button opens the :guilabel:`Create a New OGR Database Connection` dialog whose parameters are among the ones you can find in :ref:`vector_create_stored_connection`. Pressing :guilabel:`Open` you can select from the available tables for example of the PostGIS enabled database. * The last source type, |radioButtonOn| :guilabel:`Protocol`, enables to open data from the web using for example ``GeoJSON`` or ``CouchDB`` format. After selecting the type you have to fill URI of the source. .. _tip_load_from_external_drive_OSX: .. tip:: **Load layers and projects from mounted external drives on macOS** On macOS, portable drives that are mounted beside the primary hard drive do not show up as expected under :menuselection:`File --> Open...`. We are working on a more macOS-native open/save dialog to fix this. As a workaround, you can type ``/Volumes`` in the :guilabel:`File name` box and press :kbd:`Enter`. Then you can navigate to external drives and network mounts. .. index:: CSV, Delimited text files see: Comma Separated Values; CSV .. _vector_loading_csv: Importing a delimited text file ------------------------------- Delimited text file (e.g. :file:`.csv`, :file:`.txt`) can be loaded in QGIS using the tools described above. However, loaded this way, it'll show up like a simple table data. Sometimes, delimited text files can contain geometric data you'd want to visualize; this is what the |addDelimitedTextLayer|:guilabel:`Add Delimited Text Layer` is designed for. Click the |dataSourceManager| :sup:`Open Data Source Manager` icon to open the :guilabel:`Data Source Manager` dialog and enable the |addDelimitedTextLayer| :guilabel:`Delimited Text` tab, as shown in figure_delimited_text_. .. _figure_delimited_text: .. figure:: img/delimited_text_dialog.png :align: center Delimited Text Dialog First, select the file to import (e.g., :file:`qgis_sample_data/csv/elevp.csv`) by clicking on the :guilabel:`Browse` button. In the :guilabel:`Layer name` field, provide the name to use for the layer in the project (e.g., :file:`Elevation`). File format ........... Once the file is selected, QGIS attempts to parse the file with the most recently used delimiter, trying to identify fields and rows. To enable QGIS to properly parse the file, it is important to select the correct delimiter. You can specify a delimiter by activating: * |radioButtonOn|:guilabel:`CSV (comma separated values)` to use the comma character; * |radioButtonOff|:guilabel:`Custom delimiters`, choosing among some predefined delimiters like ``comma``, ``space``, ``tab``, ``semicolon``...; * or |radioButtonOff|:guilabel:`Regular expression delimiter` and entering text into the :guilabel:`Expression` field. For example, to change the delimiter to tab, use ``\t`` (this is a regular expression for the tab character). Records and fields .................. Other than settings to identify rows and fields in the data, some convenient options can be used to tweak the data recognition: * :guilabel:`Number of header lines to discard`: convenient when you want to avoid some lines to show in the import, either because those are blank lines or with another formatting. * |checkbox|:guilabel:`First records has field names`: values in the first row of data are used as field names, otherwise QGIS adds a fields row of a type ``field_1``, ``field_2``... * |checkbox|:guilabel:`Detect field types`: automatically recognizes the field type. If unchecked then all attributes are treated as text fields. * |checkbox|:guilabel:`Decimal separator is comma`: if necessary, you can force a comma to be the decimal separator. * |checkbox|:guilabel:`Trim fields`: allows you to trim leading and trailing spaces from fields. * |checkbox|:guilabel:`Discard empty fields`. As you set the parser properties, a sample data preview updates at the bottom of the dialog. Geometry definition ................... Once the file is parsed, set :guilabel:`Geometry definition` to * |radioButtonOn|:guilabel:`Point coordinates` and provide the :guilabel:`X field` and :guilabel:`Y field` if the layer is of point geometry type and contain such coordinate fields. If the coordinates are defined as degrees/minutes/seconds, activate the |checkbox|:guilabel:`DMS coordinates` checkbox; * |radioButtonOn|:guilabel:`Well known text (WKT)` option if the spatial information is represented by WKT: select the :guilabel:`Geometry field` containing the WKT definition and choose the approriate :guilabel:`Geometry field` or let QGIS auto-detect it; * If the file contains non-spatial data, activate |radioButtonOn| :guilabel:`No geometry (attribute only table)` and it will be loaded as an ordinary table. Besides the features geometry information, you can also set the layer's :guilabel:`Geometry CRS` using the |setProjection| :sup:`Select CRS` widget. Layer settings .............. Additionally, you can enable: * |checkbox|:guilabel:`Use spatial index` to improve the performance of displaying and spatially selecting features; * |checkbox|:guilabel:`Use subset index` to improve performance of :ref:`subset filters ` (when defined in the layer properties); * |checkbox|:guilabel:`Watch file` to watch for changes to the file by other applications while QGIS is running. At the end, click :guilabel:`OK` to add the layer to the map. In our example, a point layer named ``Elevation`` is added to the project and behaves like any other map layer in QGIS. However, this layer is the result of a query on the :file:`.csv` source layer (hence, linked to it) and would require :ref:`to be saved ` in order to get a spatial layer on disk. .. _import_dxfdwg: Importing a DXF or DWG file --------------------------- :file:`DXF` and :file:`DWG` files can be added to QGIS by simple drag-and-drop from the common Browser Panel. You'll be prompted to select the sublayers you'd like to add to the project. Layers are added with random style properties. .. note:: DXF files containing several geometry types (point, line and/or polygon), the name of the layer will be made from * entities *. To keep the dxf/dwg file structure and its symbology in QGIS, you may want to use the dedicated :menuselection:`Project --> Import/Export --> Import Layers from DWG/DXF...` tool which allows you to: #. import elements from the drawing file into a GeoPackage database. #. and add to the project any of the imported elements. In the :guilabel:`DWG/DXF Import` dialog, to first import the drawing file contents: #. Input the location of the :guilabel:`Target package`, i.e. the new GeoPackage file that will store the data. If an existing file is provided, then it will be overwritten. #. Specify the coordinate reference system of the data in the drawing file. #. Check |checkbox| :guilabel:`Expand block references` to import the blocks in the drawing file as normal elements. #. Check |checkbox| :guilabel:`Use curves` to promote the imported layers to a ``curved`` geometry type. #. Use the :guilabel:`Import` button to select the DWG/DXF file to use (one per geopackage). The GeoPackage database will be automatically populated with the drawing file content. Depending on the size of the \*CAD file, this could take some time. After the :file:`.dwg` or :file:`.dxf` data is imported into the GeoPackage database the frame in the lower half of the dialog is populated with the list of layers from the imported file. There you can select which layers to add to the QGIS project: #. At the top, set a :guilabel:`Group name` to group the drawing files in the project. #. Check layers to show: Each selected layer is added to an ad hoc group which contains vector layers for the point, line, label and area features of the drawing layer. The style of each layer is setup so that it resembles the look it originally had in \*CAD. #. Check whether layer should be visible at opening. #. Alternatively using the |checkbox| :guilabel:`Merge layers` option places all layers in a single group. #. Press :guilabel:`OK` to open the layers in QGIS. .. _figure_dwg_dxf_import: .. figure:: img/dwg_dxf_import_dialog.png :align: center Import dialog for DWG/DXF files .. index:: OSM (OpenStreetMap) .. _openstreetmap: Importing OpenStreetMap Vectors ------------------------------- In recent years, the OpenStreetMap project has gained popularity because in many countries no free geodata such as digital road maps are available. The objective of the OSM project is to create a free editable map of the world from GPS data, aerial photography or local knowledge. To support this objective, QGIS provides support for OSM data. Using the :guilabel:`Browser Panel`, you can load a :file:`.osm` file to the map canvas, in which case you'll get a dialog to select sublayers based on the geometry type. The loaded layers will contain all the data of that geometry type in the file and keep the :file:`osm` file data structure. .. index:: Spatialite, SQLite .. _label_spatialite: SpatiaLite Layers ----------------- |addSpatiaLiteLayer| The first time you load data from a SpatiaLite database, begin by: * clicking on the |addSpatiaLiteLayer| :sup:`Add SpatiaLite Layer` toolbar button; * selecting the |addSpatiaLiteLayer| :menuselection:`Add SpatiaLite Layer...` option from the :menuselection:`Layer --> Add Layer` menu; * or by typing :kbd:`Ctrl+Shift+L`. This will bring up a window that will allow you either to connect to a SpatiaLite database already known to QGIS, which you can choose from the drop-down menu, or to define a new connection to a new database. To define a new connection, click on :guilabel:`New` and use the file browser to point to your SpatiaLite database, which is a file with a :file:`.sqlite` extension. QGIS also supports editable views in SpatiaLite. GPS --- Loading GPS data in QGIS can be done using the core plugin: ``GPS Tools``. Instructions are described in Section :ref:`plugin_gps`. GRASS ----- Working with GRASS vector data is described in Section :ref:`sec_grass`. .. index:: Database tools, MSSQL Spatial .. _db_tools: Database related tools ---------------------- .. index:: Connecting to database .. _vector_create_stored_connection: Creating a stored Connection ............................ In order to read and write tables from the many database formats QGIS supports you'll need to create a connection to that database. While :ref:`QGIS Browser Panel ` is the simplest and recommanded way to connect and use databases, QGIS provides other tools to connect to each of them and load their tables: * |addPostgisLayer| :menuselection:`Add PostGIS Layer...` or by typing  :kbd:`Ctrl+Shift+D`; * |addMssqlLayer| :menuselection:`Add MSSQL Spatial Layer` or by typing  :kbd:`Ctrl+Shift+M`; * |addOracleLayer| :menuselection:`Add Oracle Spatial Layer...` or by typing  :kbd:`Ctrl+Shift+O`; * |addDb2Layer| :menuselection:`Add DB2 Spatial Layer...` or by typing  :kbd:`Ctrl+Shift+2`. These tools are accessible either from the :guilabel:`Manage Layers Toolbar` or the :menuselection:`Layer --> Add Layer -->` menu. Connecting to SpatiaLite database is described at :ref:`label_spatialite`. .. tip:: **Create connection to database from the QGIS Browser Panel** Select the corresponding database format in the Browser tree, right-click and choose connect will provide you with the database connection dialog. Most of the connection dialogs follow a common basis that will be described below using the PostGreSQL database tool as example. For additional settings specific to other providers, you can find corresponding description at: * :ref:`create_mssql_connection`; * :ref:`create_oracle_connection`; * :ref:`create_db2_connection`. The first time you use a PostGIS data source, you must create a connection to a database that contains the data. Begin by clicking the appropriate button as exposed above, opening an :guilabel:`Add PostGIS Table(s)` dialog (see figure_add_postgis_tables_). To access the connection manager, click on the :guilabel:`New` button to display the :guilabel:`Create a New PostGIS Connection` dialog. .. _figure_new_postgis_connection: .. figure:: img/newpostgisconnection.png :align: center Create a New PostGIS Connection Dialog The parameters required for a PostGIS connection are exposed below. For the other database types, see their differences at :ref:`db_requirements`. * :guilabel:`Name`: A name for this connection. It can be the same as *Database*. * :guilabel:`Service`: Service parameter to be used alternatively to hostname/port (and potentially database). This can be defined in :file:`pg_service.conf`. Check the :ref:`pg-service-file` section for more details. * :guilabel:`Host`: Name of the database host. This must be a resolvable host name such as would be used to open a TCP/IP connection or ping the host. If the database is on the same computer as QGIS, simply enter *localhost* here. * :guilabel:`Port`: Port number the PostgreSQL database server listens on. The default port for PostGIS is ``5432``. * :guilabel:`Database`: Name of the database. * :guilabel:`SSL mode`: SSL encryption setup. The following options are available: * :guilabel:`Prefer` (the default): I don't care about encryption, but I wish to pay the overhead of encryption if the server supports it. * :guilabel:`Require`: I want my data to be encrypted, and I accept the overhead. I trust that the network will make sure I always connect to the server I want. * :guilabel:`Verify CA`: I want my data encrypted, and I accept the overhead. I want to be sure that I connect to a server that I trust. * :guilabel:`Verify Full`: I want my data encrypted, and I accept the overhead. I want to be sure that I connect to a server I trust, and that it's the one I specify. * :guilabel:`Allow`: I don't care about security, but I will pay the overhead of encryption if the server insists on it. * :guilabel:`Disable`: I don't care about security, and I don't want to pay the overhead of encryption. * :guilabel:`Authentication`, basic. * :guilabel:`Username`: User name used to log in to the database. * :guilabel:`Password`: Password used with *Username* to connect to the database. You can save any or both of the ``username`` and ``password`` parameters, in which case they will be used by default each time you need to connect to this database. If not saved, you'll be prompted to fill the missing credentials to connect to the database in next QGIS sessions; meanwhile the connection parameters you entered are stored in a temporary internal cache and returned whenever a username/password for the same database is requested, until you close the current QGIS process. .. warning:: **QGIS User Settings and Security** In the :guilabel:`Authentication` tab, saving **username** and **password** will keep unprotected credentials in the connection configuration. Those **credentials will be visible** if, for instance, you shared the project file with someone. Therefore, it's advisable to save your credentials in a *Authentication configuration* instead (:guilabel:`Configurations` tab - See :ref:`authentication_index` for more details) or in a service connection file (see :ref:`pg-service-file` for example). Optionally, depending on the type of database, you can activate the following checkboxes: * |checkbox| :guilabel:`Only show layers in the layer registries` * |checkbox| :guilabel:`Don't resolve type of unrestricted columns (GEOMETRY)` * |checkbox| :guilabel:`Only look in the 'public' schema` * |checkbox| :guilabel:`Also list tables with no geometry` * |checkbox| :guilabel:`Use estimated table metadata` * |checkbox| :guilabel:`Allow saving/loading QGIS projects in the database`: more details :ref:`here ` .. tip:: **Use estimated table metadata to speed up operations** When initializing layers, various queries may be needed to establish the characteristics of the geometries stored in the database table. When the :guilabel:`Use estimated table metadata` option is checked, these queries examine only a sample of the rows and use the table statistics, rather than the entire table. This can drastically speed up operations on large datasets, but may result in incorrect characterization of layers (eg. the feature count of filtered layers will not be accurately determined) and may even cause strange behaviour in case columns that are supposed to be unique actually are not. Once all parameters and options are set, you can test the connection by clicking on the :guilabel:`Test Connection` button or apply it hitting :guilabel:`OK`. From the :guilabel:`Add PostGIS Table(s)`, click now on :guilabel:`Connect` and the dialog is filled with tables from the selected database (as shown in figure_add_postgis_tables_). .. _db_requirements: Particular Connection requirements .................................. Because of database type particularities, provided options are all the same for all the databases. Below are exposed these connection specificities. .. _pg-service-file: PostgreSQL Service connection file ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The service connection file allows PostgreSQL connection parameters to be associated with a single service name. That service name can then be specified by a client and the associated settings will be used. It's called :file:`.pg_service.conf` under \*nix systems (GNU/Linux, macOS etc.) and :file:`pg_service.conf` on Windows. The service file looks like:: [water_service] host=192.168.0.45 port=5433 dbname=gisdb user=paul password=paulspass [wastewater_service] host=dbserver.com dbname=water user=waterpass .. note:: There are two services in the above example: ``water_service`` and ``wastewater_service``. You can use these to connect from QGIS, pgAdmin etc. by specifying only the name of the service you want to connect to (without the enclosing brackets). If you want to use the service with ``psql`` you need to do something like ``export PGSERVICE=water_service`` before doing your psql commands. You can find all the parameters `here `_ .. note:: If you don't want to save the passwords in the service file you can use the `.pg_pass `_ option. On \*nix operating systems (GNU/Linux, macOS etc.) you can save the :file:`.pg_service.conf` file in the user's home directory and the PostgreSQL clients will automatically be aware of it. For example, if the logged user is ``web``, :file:`.pg_service.conf` should be saved in the :file:`/home/web/` directory in order to directly work (without specifying any other environment variables). You can specify the location of the service file by creating a ``PGSERVICEFILE`` environment variable (e.g. run the ``export PGSERVICEFILE=/home/web/.pg_service.conf`` command under your \*nix OS to temporarily set the ``PGSERVICEFILE`` variable) You can also make the service file available system-wide (all users) either by placing the :file:`.pg_service.conf` file at ``pg_config --sysconfdir`` or by adding the ``PGSYSCONFDIR`` environment variable to specify the directory containing the service file. If service definitions with the same name exist in the user and the system file, the user file takes precedence. .. warning:: There are some caveats under Windows: * The service file should be saved as :file:`pg_service.conf` and not as :file:`.pg_service.conf`. * The service file should be saved in Unix format in order to work. One way to do it is to open it with `Notepad++ `_ and :menuselection:`Edit --> EOL Conversion --> UNIX Format --> File save`. * You can add environmental variables in various ways; a tested one, known to work reliably, is :menuselection:`Control Panel --> System and Security --> System --> Advanced system settings --> Environment Variables` adding ``PGSERVICEFILE`` and the path of the type :file:`C:\\Users\\John\\pg_service.conf` * After adding an environment variable you may also need to restart the computer. .. _create_oracle_connection: Connecting to Oracle Spatial ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The spatial features in Oracle Spatial aid users in managing geographic and location data in a native type within an Oracle database. In addition to some of the options in :ref:`vector_create_stored_connection`, the connection dialog proposes: * **Database**: SID or SERVICE_NAME of the Oracle instance; * **Port**: Port number the Oracle database server listens on. The default port is ``1521``; * **Workspace**: Workspace to switch to. Optionally, you can activate following checkboxes: * |checkbox| :guilabel:`Only look in metadata table`: restricts the displayed tables to those that are in the ``all_sdo_geom_metadata`` view. This can speed up the initial display of spatial tables. * |checkbox| :guilabel:`Only look for user's tables`: when searching for spatial tables, restricts the search to tables that are owned by the user. * |checkbox| :guilabel:`Also list tables with no geometry`: indicates that tables without geometry should also be listed by default. * |checkbox| :guilabel:`Use estimated table statistics for the layer metadata`: when the layer is set up, various metadata are required for the Oracle table. This includes information such as the table row count, geometry type and spatial extents of the data in the geometry column. If the table contains a large number of rows, determining this metadata can be time-consuming. By activating this option, the following fast table metadata operations are done: Row count is determined from ``all_tables.num_rows``. Table extents are always determined with the SDO_TUNE.EXTENTS_OF function, even if a layer filter is applied. Table geometry is determined from the first 100 non-null geometry rows in the table. * |checkbox| :guilabel:`Only existing geometry types`: only lists the existing geometry types and don't offer to add others. * |checkbox| :guilabel:`Include additional geometry attributes`. .. _tip_ORACLE_Spatial_layers: .. tip:: **Oracle Spatial Layers** Normally, an Oracle Spatial layer is defined by an entry in the **USER_SDO_METADATA** table. To ensure that selection tools work correctly, it is recommended that your tables have a **primary key**. .. _create_db2_connection: Connecting to DB2 Spatial ^^^^^^^^^^^^^^^^^^^^^^^^^ In addition to some of the options described in :ref:`vector_create_stored_connection`, the connection to a DB2 database (see :ref:`label_db2_spatial` for more information) can be specified using either a Service/DSN name defined to ODBC or using the driver, host and port information. An ODBC **Service/DSN** connection requires the service name defined to ODBC. A driver/host/port connection requires: * **Driver**: Name of the DB2 driver. Typically this would be IBM DB2 ODBC DRIVER. * **DB2 Host**: Name of the database host. This must be a resolvable host name such as would be used to open a TCP/IP connection or ping the host. If the database is on the same computer as QGIS, simply enter *localhost* here. * **DB2 Port**: Port number the DB2 database server listens on. The default DB2 LUW port is ``50000``. The default DB2 z/OS port is ``446``. .. _tip_db2_Spatial_layers: .. tip:: **DB2 Spatial Layers** A DB2 Spatial layer is defined by a row in the **DB2GSE.ST_GEOMETRY_COLUMNS** view. .. note:: In order to work effectively with DB2 spatial tables in QGIS, it is important that tables have an INTEGER or BIGINT column defined as PRIMARY KEY and if new features are going to be added, this column should also have the GENERATED characteristic. It is also helpful for the spatial column to be registered with a specific spatial reference identifier (most often ``4326`` for WGS84 coordinates). A spatial column can be registered by calling the ``ST_Register_Spatial_Column`` stored procedure. .. _create_mssql_connection: Connecting to MSSQL Spatial ^^^^^^^^^^^^^^^^^^^^^^^^^^^ In addition to some of the options in :ref:`vector_create_stored_connection`, creating a new MSSQL connection dialog proposes you to fill a **Provider/DSN** name. You can also display available databases. .. _vector_loading_database: Loading a Database Layer ........................ Once you have one or more connections defined to a database (see section :ref:`vector_create_stored_connection`), you can load layers from it. Of course, this requires having available data. See e.g. section :ref:`vector_import_data_in_postgis` for a discussion on importing data into a PostGIS database. To load a layer from a database, you can perform the following steps: #. Open the "Add table(s)" dialog (see :ref:`vector_create_stored_connection`). #. Choose the connection from the drop-down list and click :guilabel:`Connect`. #. Select or unselect |checkbox| :guilabel:`Also list tables with no geometry`. #. Optionally, use some |checkbox| :guilabel:`Search Options` to reduce the list of tables to those matching your search. You can also set this option before you hit the :guilabel:`Connect` button, speeding this way the database fetching. #. Find the layer(s) you wish to add in the list of available layers. #. Select it by clicking on it. You can select multiple layers by holding down the :kbd:`Shift` key while clicking. #. If applicable, use the :guilabel:`Set Filter` button (or double-click the layer) to start the :guilabel:`Query Builder` dialog (See section :ref:`vector_query_builder`) and define which features to load from the selected layer. The filter expression appears in the ``sql`` column. This restriction can be removed or edited in the :menuselection:`Layer Properties --> General --> Provider Feature Filter` frame. #. The checkbox in the ``Select at id`` column that is activated by default gets the features ids without the attributes and speeds in most cases the data loading. #. Click on the :guilabel:`Add` button to add the layer to the map. .. _figure_add_postgis_tables: .. figure:: img/addpostgistables.png :align: center Add PostGIS Table(s) Dialog .. tip:: **Use the Browser Panel to speed up loading of database table(s)** Adding DB tables from their ad hoc tab of the :guilabel:`Data Source Manager` dialog to QGIS may sometimes be time consuming as QGIS fetches statistics and properties (e.g. geometry type and field, CRS, number of features) of each table beforehand. To avoid this, once :ref:`the connection is set `, it's better to use the :ref:`Browser Panel ` or the :ref:`DB Manager ` to drag and drop the database tables in the map canvas. QGIS Custom formats =================== QGIS proposes two custom formats you can load in the application using their own loading tool: * Temporary Scratch Layer: a memory layer that is bound to the project it's opened with (see :ref:`vector_new_scratch_layer` for more information) * Virtual Layers: a layer resulting from a query on other layer(s) (see :ref:`vector_virtual_layers` for more information) .. index:: QGIS Layer Definition File, QLR file QLR - QGIS Layer Definition File ================================ Layer definitions can be saved as a :ref:`Layer Definition File ` (QLR - :file:`.qlr`) using :menuselection:`Export --> Save As Layer Definition File...` in the layer context menu. The QLR format makes it possible to share "complete" QGIS layers with other QGIS users. QLR files contain links to the data sources and all the QGIS style information necessary to style the layer. QLR files are shown in the Browser Panel and can be used to add layers (with their saved styles) to the Layers Panel. You can also drag and drop QLR files from the system file manager into the map canvas. Connecting to web services ========================== With QGIS you can have access to different types of OGC web services (WM(T)S, WFS(-T), CSW ...). Thanks to QGIS Server, you can also publish these services. Description of these capabilities and how-to are provided in chapter :ref:`sec_ogc`. .. Substitutions definitions - AVOID EDITING PAST THIS LINE This will be automatically updated by the find_set_subst.py script. If you need to create a new substitution manually, please add it also to the substitutions.txt file in the source folder. .. |addDb2Layer| image:: /static/common/mActionAddDb2Layer.png :width: 1.5em .. |addDelimitedTextLayer| image:: /static/common/mActionAddDelimitedTextLayer.png :width: 1.5em .. |addLayer| image:: /static/common/mActionAddLayer.png :width: 1.5em .. |addMssqlLayer| image:: /static/common/mActionAddMssqlLayer.png :width: 1.5em .. |addOgrLayer| image:: /static/common/mActionAddOgrLayer.png :width: 1.5em .. |addOracleLayer| image:: /static/common/mActionAddOracleLayer.png :width: 1.5em .. |addPostgisLayer| image:: /static/common/mActionAddPostgisLayer.png :width: 1.5em .. |addRasterLayer| image:: /static/common/mActionAddRasterLayer.png :width: 1.5em .. |addSpatiaLiteLayer| image:: /static/common/mActionAddSpatiaLiteLayer.png :width: 1.5em .. |checkbox| image:: /static/common/checkbox.png :width: 1.3em .. |collapseTree| image:: /static/common/mActionCollapseTree.png :width: 1.5em .. |dataSourceManager| image:: /static/common/mActionDataSourceManager.png :width: 1.5em .. |dbManager| image:: /static/common/dbmanager.png :width: 1.5em .. |draw| image:: /static/common/mActionDraw.png :width: 1.5em .. |filterMap| image:: /static/common/mActionFilterMap.png :width: 1.5em .. |kde| image:: /static/common/kde.png :width: 1.5em .. |metadata| image:: /static/common/metadata.png :width: 1.5em .. |radioButtonOff| image:: /static/common/radiobuttonoff.png :width: 1.5em .. |radioButtonOn| image:: /static/common/radiobuttonon.png :width: 1.5em .. |selectString| image:: /static/common/selectstring.png :width: 2.5em .. |setProjection| image:: /static/common/mActionSetProjection.png :width: 1.5em