Geographic information plays an important role in urban planning, environmental management, agriculture, transportation and water supply. Organisations use Geographic Information System (GIS) software to collect, manage, analyse and display information connected to specific locations.
One popular GIS application is QGIS. It provides tools for creating maps, managing geographic datasets and performing spatial analysis without requiring users to purchase a commercial software licence.
But what is QGIS software, what is it used for, and how can beginners get started?
This guide explains its main features, applications and basic steps for creating your first GIS project.
What Is QGIS Software?
QGIS is a free, open-source Geographic Information System application used to view, create, edit, analyse and present geographic information.
The name QGIS originally came from Quantum GIS. The software is now officially known as QGIS.
Unlike ordinary images, geographic datasets contain information about the location and characteristics of real-world features. For example, a road dataset may contain road locations, names and classifications, while a water supply dataset may include pipeline routes, diameters and materials.
QGIS allows users to combine these datasets and work with them in one mapping environment.
It is developed by an international open-source community and distributed under the GNU General Public License. QGIS is available for Windows, macOS and Linux.
What Is QGIS Used For?
QGIS is a general-purpose GIS application used in different industries for mapping, data management and spatial analysis.
Some common applications include:
1. Mapping and Geographic Visualisation
QGIS displays geographic features such as roads, rivers, buildings, administrative boundaries and land-use areas. Users can combine datasets to produce maps showing the distribution of different features.
2. Urban Planning and Land Management
Urban planners use QGIS to map residential areas, analyse land-use changes, examine settlement growth and identify suitable locations for infrastructure development.
3. Environmental Management
Environmental professionals use QGIS to map forests, rivers, wetlands and other natural resources. Satellite imagery and elevation data can also support land-use and terrain analysis.
4. Agriculture
QGIS supports agricultural mapping, including farm boundaries, soil characteristics, terrain and vegetation information obtained from satellite imagery.
5. Water Supply and Infrastructure
Water utilities and engineering organisations can use QGIS to map water distribution pipelines, valves, pumping stations, storage tanks, customer connections and water sources.
It can also connect to PostgreSQL databases using PostGIS for managing larger spatial datasets.
Main Features of QGIS
QGIS provides several features for working with geographic information.
1. Support for Different GIS Data Formats
QGIS supports various vector and raster data formats.
Vector data represents geographic features as points, lines and polygons. Common formats include:
- Shapefile (.shp)
- GeoPackage (.gpkg)
- GeoJSON (.geojson)
- KML (.kml)
- GPX (.gpx)
Raster data represents geographic information using a grid of cells or pixels. Examples include GeoTIFF files, satellite imagery and Digital Elevation Models (DEMs).
QGIS can also connect to spatial databases and supported online geographic services.
2. Spatial Analysis and Geoprocessing
The Processing Toolbox provides tools for analysing geographic data.
Common operations include:
For example, a buffer analysis can identify buildings located within 500 metres of a river or road.
3. Map Design and Print Layout
QGIS includes a Print Layout tool for preparing professional maps.
Users can add map frames, titles, legends, scale bars, north arrows, coordinate grids and labels.
Completed maps can be exported as PDF, SVG or image files for reports and presentations.
4. Attribute Tables
Every geographic layer can contain descriptive information about its features.
For example, a water pipeline layer may include pipe diameter, material, installation year and length.
The attribute table allows users to view, filter, organise and edit this information.
5. Plugins and Python Scripting
QGIS supports plugins that extend its functionality. These can provide additional tools for data collection, mapping and specialised analysis.
The software also includes a Python console and an API called PyQGIS. These allow users with programming knowledge to automate repetitive tasks and develop customised GIS tools.
What Is the Difference Between QGIS and ArcGIS?
QGIS and ArcGIS are widely used GIS software options, but they have different licensing arrangements and ecosystems.
QGIS is suitable for users who need GIS capabilities without purchasing a commercial licence. ArcGIS provides a commercial ecosystem with its own products, services and support.
The best option depends on project requirements, budget and existing workflows.
How to Get Started with QGIS
Beginners should start with a small mapping project before exploring advanced GIS tools.
Step 1: Download and Install QGIS
Visit the official website at QGIS.org.
Open the download section and select the installer for your operating system.
The Long Term Release (LTR) is generally suitable for users who prioritise stability, while the latest release provides newer features. Check the official website for current release information.
Download and install the appropriate package, following the displayed instructions.
Step 2: Understand the QGIS Interface
After opening QGIS, create a new project.
The main interface includes:
- Browser Panel: Used to browse geographic files, folders and databases.
- Layers Panel: Displays the datasets included in the project.
- Map Canvas: The main area where geographic information appears.
- Toolbars and Menus: Provide access to mapping, editing and analysis tools.
- Processing Toolbox: Provides access to geoprocessing operations.
Step 3: Add Your First Geographic Dataset
You can practise using a sample dataset from a reliable open-data source.
To add a vector dataset:
- Open QGIS.
- Select Layer from the menu.
- Choose Add Layer.
- Select Add Vector Layer.
- Browse to your dataset.
- Click Add.
The geographic features should appear in the Map Canvas if the dataset is valid.
Step 4: Change the Layer Appearance
Right-click your layer and select Properties.
Open the Symbology section to change colours, outlines and transparency. You can also use the Labels section to display information such as road names or administrative area names.
Step 5: Save Your Project
Select Project and then Save.
QGIS projects commonly use the .qgz format. Remember that a project file generally stores references to external data sources rather than containing every dataset itself.
Keep your project and source files organised to avoid missing layers when moving the project to another computer.
Important Concepts Beginners Should Learn
- Coordinate Reference Systems (CRS): A CRS defines how geographic locations are represented on a map. Incorrect CRS information can cause layers to appear in unexpected locations or produce misleading measurements. Use a suitable projected CRS for accurate distance and area calculations.
- Vector and Raster Data: Vector data represents features as points, lines and polygons, while raster data represents information using a grid of cells. For example, pipelines are usually represented as lines, while satellite imagery is raster data.
- GIS Data Management: Use meaningful file names, document data sources, maintain consistent coordinate systems and keep backups of important datasets.
Common Beginner Mistakes
Avoid these common problems when working with QGIS:
- Ignoring coordinate reference systems.
- Moving or renaming source files without updating project references.
- Forgetting to save layer edits.
- Installing unnecessary or incompatible plugins.
- Using geographic datasets without checking their source, date and accuracy.
- Good data management makes GIS projects easier to maintain and share.
Conclusion
QGIS is a free, open-source GIS application that provides tools for geographic data management, mapping, spatial analysis and map production.
Its support for vector and raster data, geoprocessing tools, plugins and spatial databases makes it useful in agriculture, environmental management, urban planning and water infrastructure.
If you are beginning your GIS journey, start by adding geographic data, managing layers, changing map styles and exporting a simple map. These basic skills provide a foundation for more advanced GIS applications.
Also you may learn: What Is ArcGIS? Features, Uses, Applications and Beginner's Guide
Frequently Asked Questions
1. Is QGIS software free?
Yes. QGIS is open-source software distributed under the GNU General Public License.
2. What is QGIS used for?
It is used for mapping, geographic data management, spatial analysis, environmental monitoring, urban planning and infrastructure mapping.
3. Is QGIS suitable for beginners?
Yes. Beginners can start with simple mapping exercises and gradually learn advanced tools.
4. What is the difference between QGIS and Quantum GIS?
Quantum GIS was the original name of the project. The software is now known as QGIS.
5. Can QGIS open Shapefiles?
Yes. QGIS supports Shapefiles, GeoPackage, GeoJSON, KML and other common geographic formats.
6. Can QGIS connect to PostGIS?
Yes. QGIS can connect to PostgreSQL databases with PostGIS enabled.
7. Is QGIS better than ArcGIS?
Neither is automatically better for every user. QGIS is free and open source, while ArcGIS provides a commercial software ecosystem. The right choice depends on the project and its requirements.
8. Where can I download QGIS?
You can download QGIS from its official website: https://qgis.org/.
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