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QGIS Institute

Introduction to GIS and QGIS

Introduction to GIS and QGIS

Discover what a Geographic Information System is, and understand why QGIS has become the world's leading Free and Open Source GIS platform.

Learning objective: By the end of this lesson, you will be able to define what a GIS is and describe the role of QGIS as an Open Source GIS application.

Level: Beginner|≈ 20 min reading|4 sections|1 exercise

Welcome to the World of Geographic Information Systems

A Geographic Information System (GIS) is a powerful technology designed to capture, store, manipulate, analyze, and visualize data that has a spatial or geographic component. In other words, a GIS allows you to work with any information that can be linked to a location on Earth — from a country's boundaries to the position of a single tree.

As spatial awareness becomes increasingly important across industries, GIS has emerged as an essential tool for decision-making in fields such as:

  • Urban planning and infrastructure management
  • Environmental monitoring and natural resource management
  • Forestry, agriculture, and land use analysis
  • Public health, emergency response, and logistics
  • Cartography and thematic map production

What does a GIS actually do?

A modern GIS application typically allows you to perform four major categories of tasks:

  1. 1Data viewingDisplay geographic data in the form of layered maps.
  2. 2Data capture and editingCreate and modify vector and raster datasets.
  3. 3Spatial analysisRun advanced geoprocessing operations such as intersections, buffers, distance calculations, and interpolation.
  4. 4Map productionGenerate sophisticated maps, atlases, and reports for communication and publication.

In a GIS, information is typically organized into layers. Each layer represents a particular type of feature (for example, roads, rivers, or land parcels) and can be displayed, queried, and analyzed independently or in combination with others. This layered approach is what makes GIS so flexible and powerful for understanding relationships between different phenomena in space.

What is QGIS?

QGIS is a Free and Open Source Geographic Information System designed to be user-friendly while providing all the common functions and features expected from a professional GIS.

A brief history

The QGIS project was born in May 2002 and was established as a project on SourceForge in June of the same year. From the beginning, the goal was clear: to make GIS software — which has traditionally been expensive proprietary software — available to anyone with access to a personal computer.

What started as a simple GIS data viewer has evolved into a complete platform used today for:

  • Daily GIS data-viewing needs
  • Data capture and editing
  • Advanced GIS analysis
  • Sophisticated map, atlas, and report production

Open Source and free

QGIS is released under the GNU General Public License (GPL). This license guarantees two fundamental freedoms:

  • You can inspect and modify the source code.
  • You will always have access to a GIS program that is free of cost and free to modify.

QGIS is developed by a community of dedicated volunteers and organizations who strive to be a welcoming community for people of all backgrounds.

Cross-platform and modern

QGIS currently runs on most Unix platforms, Windows, and macOS. It is developed using the Qt toolkit and C++, which gives it a snappy feel and a pleasing, easy-to-use graphical user interface (GUI). Independent companion applications also allow QGIS workflows to be taken into the field on Android and iOS devices.

"It's free, as in lunch. Installing and using the QGIS program costs you a grand total of zero money. No initial fee, no recurring fee, nothing." — QGIS official training manual

QGIS: A Family of Applications

QGIS is not just one program — it is actually a suite of related applications that share the same engine and visualization libraries. Understanding this ecosystem will help you choose the right tool for the right task.

QGIS Desktop

The map designer. Provides the GUI where you create and modify maps, edit data, run analyses, and design layouts — menus, toolbars, a map canvas, layers list, and panels.

QGIS Server

The map server. An open-source implementation of OGC web services (WMS, WFS, WCS, OGC API - Features) that publishes your .qgs project files on the web — identical rendering to Desktop.

PyQGIS & Python Console

A plugin architecture exposing a complete Python API. Developers interact with layers, features, and the interface itself to automate tasks and extend QGIS.

Standards and interoperability

QGIS supports a wide variety of data formats and standards, including:

  • Vector formats: GeoPackage (the default), Shapefile, SpatiaLite, GPX, KML, and many database connections (PostgreSQL/PostGIS, Oracle Spatial, MS SQL Server, SAP HANA…).
  • Raster and mesh formats: a wide range supported through GDAL and MDAL drivers.
  • Web services: WMS, WMTS, WFS, WCS, CSW, XYZ tiles, ArcGIS REST, and STAC catalogs.
  • Approximately 7,000 Coordinate Reference Systems (CRSs) with automatic on-the-fly reprojection.

Why Learn QGIS?

Learning QGIS gives you access to a complete, professional-grade GIS platform without any licensing barriers. Here are the main reasons why QGIS has become a standard choice for individuals, organizations, and even governments:

1

A wealth of features

Identify, select, edit, view, and search features and attributes; data-defined labeling and symbology; spatial bookmarks and annotation tools; atlas map composition; north arrows, scale bars, and rich print layouts; a locator bar to search functions and datasets.

2

A powerful processing framework

A complete geoprocessing environment that lets you call native and third-party algorithms directly from QGIS — or from the command line using qgis_process — making spatial analysis more productive and reproducible.

3

A vibrant ecosystem

Developed by a team of dedicated volunteers and organizations worldwide. A multi-language application with documentation available in many languages, ensuring accessibility for users across the globe.

4

A path to professional skills

Mastering QGIS unlocks transferable skills: coordinate reference systems, vector and raster data models, symbology, spatial analysis, cartographic design, and web mapping standards (OGC) — portable to any GIS software.

In the next lessons of this module, you will discover the QGIS user interface, learn to load and manage geographic data, and start working with symbology to produce your first professional maps.

Exercise

Practical exercise: Identifying GIS concepts

Read the following short scenarios and answer the questions below.

A

A biologist creates a digital map of bird observations. Each point on the map represents a single bird sighting, with attributes such as species name, date, and observer. She uses QGIS to count how many observations fall within a national park boundary.

B

A web developer sets up a service that delivers map tiles of a city's bicycle network to a public website. The maps are configured in a QGIS project file on a server.

C

A student wants to install GIS software on his personal laptop but has no budget to buy a commercial license.

  1. In Scenario A, what type of GIS task is being performed (data viewing, data capture, spatial analysis, or map production)?
  2. In Scenario B, which QGIS application is most likely being used?
  3. In Scenario C, which key feature of QGIS solves the student's problem? Cite the license name.
Show correction

Question 1 — Scenario A: The biologist is performing spatial analysis. Specifically, she is using a point-in-polygon operation (counting features within a boundary), which is a classic GIS analytical task. She is also doing some data viewing, but the core task described — counting observations within a polygon — is analytical.

Question 2 — Scenario B: This scenario describes QGIS Server. QGIS Server is the server-side application that uses QGIS project files as input and serves them via OGC web services such as WMS or WMTS to web clients. Remember: QGIS Desktop is the map designer, while QGIS Server is the map server.

Question 3 — Scenario C: QGIS solves the student's problem because it is Free and Open Source Software. It is released under the GNU General Public License (GPL) version 2 or any later version. This means installing and using QGIS costs zero money — no initial fee, no recurring fee, nothing — and the user can even inspect and modify the source code if desired.

Key points to remember

  • A Geographic Information System (GIS) captures, stores, manipulates, analyzes, and visualizes data linked to geographic locations, organized in layers.
  • GIS supports four main task categories: data viewing, data capture, spatial analysis, and map production.
  • QGIS is a Free and Open Source GIS application, born in May 2002, designed to make GIS accessible to anyone with a personal computer.
  • QGIS is released under the GNU General Public License (GPL), guaranteeing free use, free modification, and free access to the source code.
  • QGIS is cross-platform: it runs on Windows, macOS, and most Unix systems, and is built with C++ and the Qt toolkit.
  • The QGIS ecosystem includes QGIS Desktop (the map designer), QGIS Server (the map server publishing OGC services like WMS, WFS, WCS), and PyQGIS (the Python API for automation and plugin development).
  • Because QGIS Desktop and QGIS Server share the same visualization libraries, web maps look identical to desktop maps.
  • QGIS supports a vast number of formats and standards — GeoPackage is the default vector format — and approximately 7,000 Coordinate Reference Systems with automatic on-the-fly reprojection.
  • The QGIS plugin architecture allows users to extend functionality easily, with many plugins written in Python.
  • QGIS is developed by a welcoming, volunteer-driven community and is available in many languages.
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