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Getting Started with QGIS

QGIS is a user friendly Open Source Geographic Information System (GIS) licensed under the GNU General Public License. QGIS is an official project of the Open Source Geospatial Foundation (OSGeo). It runs on Linux, Unix, Mac OSX, Windows and Android and supports numerous vector, raster, and database formats and functionalities.

The user interface can be customised according to your preferences - Toolbars and Panels can be turned on and off, docked, tabbed (in the case of panels), or can be floating. The default installation starts off looking a bit busy, so start by customising to tidy up and reflect your preferences - you only need to do this once.

Toolbars

  1. Change the size of the toolbar icons to 16pt using Settings > Options > General > Application > Icon size

  2. Add/remove toolbars and panels by right-clicking in the toolbar area, or by using the checkboxes in View > Toolbars - at this stage, turn all of them off apart from Attributes, Data Source Manager, Map Navigation, Project, and Selection

  3. Move the Layers panel to the top

Your screen will now look something like this:

Coordinate Reference System (CRS)

The coordinate reference system should reflect the area you are working in - it can be changed later if your data covers a different area. Set QGIS to default to your local or usual CRS. QGIS can open data which uses CRSs which are referenced using the European Petroleum Survey Group (EPSG) numbering system.

In this course, which uses UK-based data, the data uses one of the following CRS:

  • EPSG 27700: OSGB 1936 British National Grid

  • EPSG 4326: WGS 84 (Long / Lat)

  • EPSG 3857: WGS 84 Pseudo Mercator (used by e.g. Google Maps, OpenStreetMap)

Data will normally include details of its CRS, and a QGIS project will also have a CRS setting. Translation is done on the fly by default, so all layers are displayed using the CRS of the project.

CRS Settings

  1. Change CRS settings so that the defaults are correct for this course, go to Settings > Options > CRS and Transforms > CRS Handling  and set the defaults to British National Grid as in the screenshot below using the button on the far right of the dropdown, and set the Accuracy Warning to 10 meters as well (this cuts down warning notifications)

When you set a CRS - for example as a default for new projects, or as a custom setting for a specific project - you will see this dialog, with a Filter field at the top which searches by name or EPSG number:

Panels

The Layers and Browser panels are shown by default.

Layers

  1. Go to Project > Open, select the Home Folder and browse to the project file .../QGIS Training/Essentials /Essentials_01_gettingstarted.qgz

  2. Drag and drop to rearrange the layers so that they are ordered in a way that they are all visible in the map

  3. Create a group using the Add Group button in the Layers panel , and put some of the layers in it

  4. Right-click > Rename Layer on each layer and use descriptive names to replace their existing file names

  5. Zoom to a scale where the layers are all readable

  6. Turn on and off layers to see the effect on the map

  7. Right-click on a layer for a menu of options for an individual layer

  8. Double-click on a layer to go straight to its Properties dialog - this holds information and functionality in a tabbed dialog

Browser

The Browser is the QGIS equivalent of Windows Explorer or ArcCatalog - it shows the spatial data sources available to you, including those in:

  • Local and network drives

  • Database connections

  • Web services connections such as WFS and WMS

Browser Navigation

  1. In the Browser, navigate to D:\PhotonUser\My Files\Home Folder\QGIS Training\Data\vector, then double-click on a layer to load it into the map

  2. Right-click on the layer in the Browser to show other options (this will vary according to the data and source), and try using any of them

Information Bar

The Information Bar below the map window provides information and controls relating to the current map and environment. From left to right:

  • The Search box on the left will search for loaded layers, and also for processing functions (buffer, statistics, clip etc.).

  • Coordinate dynamically shows the current location of the cursor in the CRS of the project. Enter coordinates manually and press enter to centre the map on a point. The toggle button to the right will switch the coordinate display to show the Extent of the map canvas.

  • Scale reflects the current scale of the map view, and can be set manually or to pre-sets. The padlock icon to the right locks the scale, and causes the mouse wheel or other zoom controls to magnify the map without changing the scale, so that any scale-dependent triggers would not be activated.

  • Magnifier changes the extent of the map view without changing the scale, and can be set manually or with pre-sets.

  • Rotation rotates the entire view by the degrees setting - so that North is no longer up.

  • Render, if unchecked, will suppress refreshing of the screen whenever it is zoomed or panned, and is useful when large numbers of features are displayed, slowing down refresh performance

  • The EPSG setting shows the CRS EPSG code for the current project - this can be changed by clicking on the setting. 

  • The bubble icon on the far right will open the Log Messages Panel, showing any messages generated by QGIS in the session.

  1. Change some of the settings in the Information Bar - for example Scale and Rotation - to see how this changes the map

  2. Change the EPSG code setting (the CRS) to WGS 84 to see the effect on the appearance of the map, then change it back to British National Grid

Projects

QGIS stores all project data in a file with a .qgz extension (this is actually a zip file which includes the project file in XML as a .qgs file). This file includes anything you create in the project, including:

  • Layers and layer order

  • Styles and labelling

  • Map windows setup

  • Queries

  • Joins

  • Project properties

  • Print Layouts

Note that source data is not saved in the project file, but remains in its source files or databases - the project file just holds pointers to it.

Open, close, and save projects from the menu or toolbar. You can also navigate to the project file in the Browser Panel or file explorer, and drag it into QGIS to open it.

There is no autosave in QGIS - save your project frequently to avoid disappointment.

Project Properties

  1. Go to Project > Properties to show this dialog, which sets properties for the current project, overriding settings you make in the Settings > Options dialog

  2. Click through the tabs to get an idea of settings that can be changed

Plugins

Plugins are used to extend the scope of QGIS, improve on native functionality, or address specialist needs.

Plugins may be:

  • Core plugins: installed by default, but may be turned on or off 

  • Official plugins: from the QGIS Official Plugin Repository

  • Other plugins: installed from a zip, or from another repository

Plugin Management

  1. Go to Plugins > Manage and Install Plugins

  2. In the Settings tab, check Show also Experimental Plugins

  3. Browse / search the list of plugins under All, and make sure you have QuickMapServices and QGIS Resource Sharing installed - if not install them

  4. Using QuickMapServices (it should now be in the Web menu), add the OSM Standard layer

  5. Install any other plugins which might be of interest to you