The Fundamentals

Published

March 2, 2026

What are we going to learn?

In this workshop, we will learn about:

  • The QGIS interface
  • Loading a basemap
  • Setting up a project
  • Vector vs Raster Data
  • Identifying and selecting spatial features
  • Personalising the look of the map
  • A basic map export
  • Finding help and learning more

Interface

When we open QGIS, we can see the 3 main elements of the interface:

  • the Browser panel, to navigate our file system and data sources
  • the Layers panel, to organise the different layers that compose our map
  • the Canvas, where we see the map (at startup, QGIS uses that space to show recent projects and QGIS news)

New project and basemap

  • Create a new project with Project > New.

  • We can straight away load an OpenStreetMap basemap to have a background: in the Browser panel, XYZ Tiles > OpenStreetMap.

Controls

The default mouse mode is Pan Map, which allows to drag the map around. We can use the mouse wheel to zoom in and out, and press the Ctrl key to use more precision.

What is Spatial Data?

What is spatial data? Most broadly-speaking, data is spatial when it has coordinates, and therefore a coordinate reference system (see more on this below). Coordinates define the longitude (x) and latitude (y) of where data is located across the globe.

mapschool.io is a fantastic resource for a simple explanation of many spatial concepts.

Spatial data types

There are three broad classes of spatial data that you may encounter.

  1. Vector

  • Vector data can be points, lines, or polygons. Quite typically vector data is stored as shapefiles (.shp), although there are many file formats to store vector data. My go-to is geopackages (.gpkg) (more on this later).

  • Often, vector data have multiple attributes, meaning that different variables have been measured for each vector geometry.

  1. Raster
  • Raster data is gridded data, where each ‘grid cell’ (also referred to as a ‘pixel’) stores a data value. Data can be categorical (e.g. land use classes) or continuous (e.g. temperature).
  • Grids can be regular, irregular, curvilinear, etc.
  1. Spatiotemporal data cubes
  • Spatiotemporal data cubes are when vector or raster data have an additional dimension beyond x & y coordinates: time.

Case Study - Windfarm Proposal

We have been asked to explore the feasibility of constructing a Windfarm on Enoggera Hill, which is part of the Enoggera Army Base (Gallipoli Barracks).

Throughout these workshops we are going to make maps and run spatial analyses that are useful in a wide variety of disciplines and relate to this particular case study. This scenario of a Windfarm Proposal allows us to use spatial analyses to explore concepts connected to the environment, health, culture, and landscape.

We will create a project folder, bring in different kinds of data, run a variety of spatial analyses, and export a few maps.

While the location and data we will be using are all real, this scenario is entirely fictional.

Project Folder Structure

We will start by creating a good folder structure to work within. This folder is where our project, our data, and creations will live. Folder structure is very important for keeping your data tidy, as well as for ease of sharing your project with others. You simply need to zip the project folder if you need to share the whole thing.

  • Let’s save our project: Project > Save.

  • Navigate to where you want to save your project, and create a new folder, let’s call it “Enoggera_Windfarm_26”.

  • Inside that folder, create these folders:

  • “data” - for all the data we will use to make our maps, split into:

    • “raw” - raw data from your research or the Internet

    • “processed” - any data you’ve modified

  • “output” - for any maps or images we export

  • “temp” - this folder isn’t necessary, but when you’re playing around and testing, it can be helpful to stop things getting messy.

  • Finally, let’s save our .qgz project file inside the “Enoggera_Windfarm_26” folder, named “Enoggera_Windfarm_26.qgz”

Your .qgz file should always be in the highest level folder, so it’s only looking down into folders for data, not back out. This might feel unnecessary now, but things quickly get out of control and hard to find if you don’t have a good folder structure.

Data Download

The data for this session can be directly downloaded from this link.

Once downloaded, extract the archive into your raw folder within your data folder.

This data folder contains all of the data that we will be using in these workshops. We’re going to bring the data into our project lesson by lesson.

To start with, we’re going to import some project files that show us where our development will take place.

Importing data

To add our own data:

  • Go to the menu Layer > Add Layer > Add Vector Layer...

  • Open your folders data > raw > 1-fundamentals_data

  • Choose the “Turbine_Locations_SEQ.gpkg” file, and click “Add”. It is now in your Layers panel.

If you’ve already loaded in the OpenStreetMap Basemap, then you should get the popup Select Transformation for Project Area. This is asking you how you want to deal with the difference between the basemap’s projection and the projection of your data. Projections are how we stretch “spherical” data to fit on a flat rectangular map, which we will cover in detail later in this workshop. Fortunately, for now, QGIS will handle this on the fly for us so we can simply click OK.

So where is the data? If you want to zoom in to your data, you don’t have to use your mouse, you can use the Zoom Full button, or right-click on your Turbine_Locations_SEQ layer and select Zoom to Layer(s).

You can also use the Project Home directory in the browser to add another layer:

  • Click the Project Home dropdown, then data > raw > 1-fundamentals_data
  • Try loading the “Project_Area.gpkg” and “Proposed_Access_Track.gpkg” GeoPackages (format .gpkg), by drag-and-dropping or double-clicking.

All layers are visible in the Layers panel, with the most recently loaded by default at the top. Layers are rendered as they are listed, which means the top ones will cover the bottom ones. Make sure you optimise the order for your map!

You can also turn the layer visibility on and off from this panel with the tick box.

You might notice that QGIS randomly chooses a colour for your data when you import it. We can change these colours later.

Data Summary

You should now have the following layers

  • Project_Area (polygon)
  • Proposed_Access_Track (line)
  • Turbine_Locations_SEQ (point)
  • OpenStreetMap (basemap)

Learn about the data

You can open the attribute table to see tabular data contained in each layer. (Right-click on a layer and use “Open Attribute Table”. Alternatively, use the top toolbar button or use F6.)

You can also use the Identify Features tool in the top toolbar. This allows you to learn about specific features included in the currently selected layer.

Subset the data

We currently have data from two proposed Windfarm locations, which you can confirm by using the Zoom Full button. However, we no longer need the Mt Coot-Tha data.

To remove the unneeded points, we can do the following:

  1. Select the “Turbine Locations SEQ” layer
  2. Use the Select Features button, and draw a rectangle around Enoggera Hill, so all the points appear in yellow
  3. Right-click on the “Turbine Locations SEQ” layer and use Export > Save Selected Features As...
  4. Name the new layer as “EH Turbines” and name the file “EH_Turbines” in your project directory, and click OK.

The new layer is loaded to the map by default.

Notice how we keep using “_” underscores in our file names instead of spaces? Spaces in file names can cause some functions to fail to run, so it’s worth practicing that. Spaces in layer names is fine - these are purely for display.

Clip

Instead of just using selections, we can also clip out the data we want by using a polygon layes as an overlay layer.

We’ll use the Clip tool on the final piece of data for this session: the Broad Vegetation Groups (BVGs) for this area. BVG data shows us what vegetation types are found in a particular location. We’ve downloaded a section of this data from QSpatial. Currently it covers a wide area, but we want to focus it down to our project.

Use the Project Home directory in the browser to add the “BVG_SEQ.shp” file.

So far we have only used .gpkg GeoPackage files, the VG_SEQ.shp is a Shapefile. Both of these are common vector data types. Shapefiles are more established and widely used, where GeoPackages are leaner and more customisable. You can leave the shp files inside the zip folder and still access and edit them - most other file types will require you to extract them before you can edit them.

This layer is not very pretty at the moment, but we can change the symbology after we subset the data.

Follow these steps to Clip:

  1. Select the layer you want to clip, in this case BVG_SEQ
  2. Use the Vector > Geoprocessing Tools > Clip... tool
  3. Use the Project Area layer as the overlay.
  4. Click Run

We should get an error Feature (242) from “BVG SEQ” has invalid geometry. Never fear, we can fix this!

This is caused by little issues in the polygon layer. Sometimes when polygons are drawn or exported from online sources, they will create errors, and sometimes little slither polygons on the edges. We can investigate the source of these errors using the Check validity tool, but for today, we’re simply going to fix them with the Fix Geometries tool from the Processing Toolbox.

The Processing Toolbox is full of useful tools for data analysis and data management.

Before we do this, let’s remove the failed Clipped layer. Right-click on the Clipped layer and select Remove Layer...

Fix Geometries

  • Open the Processing Toolbox by clicking the cog icon from the top menu Processing Toolbox (alternatively go to View > Panels > Processing Toolbox)
  • In the Processing Toolbox panel, Search for “Fix geometries”
  • Double-click on the Fix geometries option
  • In the Fix Geometries window, select BVG SEQ from the Input layer options, then click Run
  • Right click Fixed Geometries in the Layer panel, click Rename Layer, and change it to BVG Fixed

You can now re-run the Clip tool with the resulting BVG Fixed layer (instead of the BVG SEQ layer)

  • Go to Vector > Geoprocessing Tools > Clip
  • Under Input Layer select BVG Fixed
  • Under Overlay Layer select Project Area
  • Click Run

Magic. Our new layer has the BVG data cookie-cut to the Project Area shape.

Notice how the clipped layers also doesn’t have a descriptive name? Make sure you rename them. Let’s change Clipped to EH BVG

You can now hide the original “BVG SEQ” and “Turbine Locations SEQ” layers.

Saving your project

It’s always a good idea to regularly save your progress.

You can save your project with the floppy disk icon, or using Ctrl + S, and the project should be visible in a list when you re-open QGIS again.

Temporary Scratch Layers

Notice the little icon next to some of your layers? We have created “temporary scratch layers”: they are basically temporary files that will disappear when we close QGIS. This is useful if you keep processing data and creating new layers that you want to discard afterwards. In our case, we do want to keep the “EH BVG” layer, so we need to save it to a file. If we try to close QGIS with scratch layers loaded, it will give you a warning that they will be lost in the process.

You can click on the scratch layer icon to save the file. In the dialog, we can give the layers a File name (in our project’s home directory) and click OK.

Personalise your map

Change the symbology

Our vector layers are assigned a random colour when we load them. We now want to make them look better.

Double-click on the Project Area layer to open the Layer Properties click the Symbology tab, and use Color to change to a better colour. Click Apply. Perhaps we’d be better off with no fill, and work more with the border by clicking on Simple fill. Change the Fill Style to No Brush. We can now go into more details about the Stroke color, width and style.

We can make more complex fills by adding an extra “symbol layer”, and layering different kinds of fill styles. Try this with both polygons and lines. For example, style the Proposed Access Track so they look like roads (the topo road preset is a good start).

Now try to change the point symbology of our EH Turbines layer: we don’t have to stick to Simple marker. Try for example the different icons available with Symbol layer type > SVG marker or Font marker selected.

The Properties dialog is quite large and makes it difficult to see the changes in symbology. You can use the “Layer Styling Panel” (button in the Layers panel, or F7 shortcut) to use a side panel instead, with the “Live update” option on by default.

Classifying the symbology

What if we want to colour according to a variable? Depending on the type of variable, we can choose “Categorised” (for categorical data) or “Graduated” (for continuous data).

We can do this with our EH BVG data:

  1. Click on the Layer Styling Panel button
  2. Change from “Single Symbol” to “Categorised”
  3. Use the bvg1m column in the “Value” field
  4. Pick a relevant colour ramp
  5. Click “classify”

The colours may not be very pretty right now, but at least we can differentiate them. We will make these much nicer later.

Add labels

Have a look at the attribute table for our EH Turbines layer. What could we use to label our points?

Double-click on the EH Turbines layer: Labels and then click No Labels > Single labels. You can also use the Layer Labelling Options button to open the sidebar, which allows you to “Live update” the map when you change a setting.

Choose Value > turb_id to label with the Turbine IDs. In the “Text” tab, we can change the look of our labels: amend the size, the colour, the font… We can also add a text buffer with the Buffer tab to make them more readable.

The placement tab allows us to fine-tune the placement of the labels in reference to the points. The default mode is “Cartographic”, and we can increase the distance to the symbol used. If we want the label to cover the point, we can use Mode > Offset from point and use the middle quadrant. We might also want to set the layer’s Symbology to “No Symbols”.

Simple Map Export

You can export your map with a very customised layout, or you can do a simple export. This morning we will look at the simple map export.

Zoom to the level of detail you want your image to contain.

To export out your map:

  1. Go to Project > Import/Export > Export Map to Image...

  2. Choose Draw on Canvas and draw the area you want to export

  3. Increase the Resolution to 300 DPI

  4. Click Save

  5. Navigate to where you want to save your image (we created the “output” folder for that), name it, and click Save

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