Quantum GIS Guide

Last updated on 2026-06-22 | Edit this page

Estimated time: 45 minutes

Overview

Questions

  • What is QGIS and why is it useful?
  • How do I install QGIS on my system?
  • How do I load spatial data into QGIS?
  • How can I style and visualize data on a map?
  • How do I export a finished map?

Objectives

  • Install QGIS successfully
  • Understand the QGIS interface
  • Load and explore spatial datasets
  • Create and style a simple map
  • Export a publication-ready map

What is QGIS?

QGIS (Quantum GIS) is a free, open-source Geographic Information System (GIS) used to:

  • Visualize spatial data
  • Analyze geographic patterns
  • Create professional-quality maps
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Why QGIS?

QGIS is widely used in academia, industry, and government — and it is completely free. It supports a wide range of vector and raster formats, connects to spatial databases, and has a rich plugin ecosystem.

Installing QGIS

Step 1: Download QGIS

  1. Go to the official QGIS website: Here: https://qgis.org

  2. Click Download Now

  3. Choose the appropriate version for your operating system:

    • Windows → Use the Standalone Installer (LTR) for the most stable release
    • Mac → Download the macOS package
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Which version should I choose?

QGIS offers a Latest Release and a Long Term Release (LTR). For workshops and beginners, the LTR is recommended because it is more stable and better tested.

Step 2: Install QGIS

  • Run the downloaded installer
  • Keep the default settings (recommended for beginners)
  • Wait for the installation to complete

Step 3: Launch QGIS

  • Open QGIS Desktop from your applications menu
  • You should see the main interface

Understanding the QGIS Interface

QGIS Interface Features.
QGIS Interface Features.

Key Components

  • Map Canvas → The central area where your map is displayed
  • Layers Panel → Shows all loaded datasets; controls layer visibility and order
  • Browser Panel → Lets you navigate and access files on your system
  • Toolbar → Tools for navigation, selection, and editing
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Tip

If a panel is missing, you can enable it via View → Panels.

Loading Spatial Data

QGIS supports many spatial data formats. The most common are:

  • Shapefiles (.shp) — a widely used vector format
  • GeoJSON (.geojson) — lightweight, text-based vector format
  • GeoPackage (.gpkg) — a modern, self-contained format (recommended)
  • CSV with coordinates — tabular data with latitude/longitude columns
  • Raster files (.tif, .img) — gridded data such as satellite imagery or elevation models

Adding a Vector Layer

  1. Go to Layer → Add Layer → Add Vector Layer
  2. Browse to your file (e.g., a .shp or .geojson file)
  3. Click Add, then Close

The layer will appear in the Layers Panel and display on the Map Canvas.

Adding a CSV with Coordinates

  1. Go to Layer → Add Layer → Add Delimited Text Layer
  2. Select your .csv file
  3. Set the X field (longitude) and Y field (latitude)
  4. Choose the appropriate coordinate reference system (CRS) — EPSG:4326 is common for lat/lon data
  5. Click Add
Discussion

Exercise 1: Load and Explore a Dataset

  1. Download a sample shapefile from a public source (your instructor will provide one, or try Natural Earth)
  2. Open QGIS and add the shapefile as a vector layer
  3. Right-click the layer in the Layers Panel and select Open Attribute Table
  4. Explore the data: How many features are there? What columns are available?

Styling and Visualizing Data

Once your data is loaded, you can change how it looks on the map.

Changing Layer Style

  1. Right-click the layer in the Layers Panel
  2. Select Properties → Symbology
  3. Choose a style type:
    • Single Symbol — one color for all features
    • Categorized — different colors by category (e.g., land use type)
    • Graduated — a color ramp based on numeric values (e.g., population density)
  4. Adjust colors, borders, and opacity as needed
  5. Click Apply, then OK

Adding Labels

  1. Open Layer Properties → Labels
  2. Set the label type to Single Labels
  3. Choose the field to display (e.g., a name column)
  4. Adjust font size and placement as needed
  5. Click Apply
Discussion

Exercise 2: Style Your Map

  1. Using the layer you loaded in Exercise 1, open the Symbology tab
  2. Change the style from Single Symbol to Categorized or Graduated (depending on your data)
  3. Choose a column to classify by and pick a color ramp
  4. Apply the style and observe how the map changes
  5. Add labels for a text field of your choice

Exporting a Map

QGIS includes a Print Layout tool for creating publication-ready maps.

Creating a Print Layout

  1. Go to Project → New Print Layout
  2. Give your layout a name and click OK
  3. The Print Layout window will open

Adding Map Elements

  • Add the map: Go to Add Item → Add Map, then draw a rectangle on the canvas
  • Add a title: Add Item → Add Label, then type your title
  • Add a legend: Add Item → Add Legend
  • Add a scale bar: Add Item → Add Scale Bar
  • Add a north arrow: Add Item → Add North Arrow (or Add Picture and select a north arrow image)

Exporting

  • Export as Image: Layout → Export as Image (PNG, JPEG)
  • Export as PDF: Layout → Export as PDF
  • Export as SVG: Layout → Export as SVG
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Tip

For the best print quality, export as PDF. For web use, PNG at 150–300 DPI works well.

Troubleshooting

  • Layer not displaying? Check that the CRS matches your other layers. Right-click the layer → Set CRS → Set Layer CRS.
  • QGIS running slowly? Large raster files or complex vector layers can slow things down. Try zooming into a smaller area or simplifying your data.
  • Plugin not working? Go to Plugins → Manage and Install Plugins and check for updates.
  • Need help? Raise your hand during the workshop.
Key Points
  • QGIS is a free, open-source GIS application suitable for mapping, visualization, and spatial analysis.
  • Spatial data can be loaded from shapefiles, GeoJSON, GeoPackage, CSV, and raster formats.
  • The Symbology panel controls how data appears on the map — use categorized or graduated styles to highlight patterns.
  • The Print Layout tool lets you compose and export professional maps with titles, legends, and scale bars.