Amogh N P
✦ In loving memory of Amogh N P — Architect · Designer · Visionary ✦
A planner's screen showing a city Geographic Information System with several coloured map layers — roads, land-use zones and contours — stacked and partly peeled apart to reveal the layering.
Unit IGIS Modelling in Urban & Regional Planning

Introduction to GIS

Not a digital map — a system that links place to data.

≈ 45 min + lab task

A Geographic Information System is widely mistaken for "a digital map". It is far more: a system that links every place to its data and lets you ANALYSE both — the planner's instrument for the question "where". Learn what a GIS really is and how it stores the world in layers; map analysis and automated cartography; coordinate systems and projections (and why you cannot flatten a sphere without distortion); and the standard GIS packages.

Learning objectives

By the end of this lesson, you will be able to — mapped to the course outcomes for GIS Modelling in Urban & Regional Planning:

1
CO1 · Understand

Explain what a GIS is and how it stores the world in layers.

2
CO1 · Understand

Explain map analysis and automated cartography.

3
CO1 · Understand

Explain coordinate systems and projections.

4
CO1 · Understand

Identify the standard GIS packages.

Place + data + analysis

What a GIS is

A GIS links place to data and analyses both — holding the world in layers; a map only displays, while a GIS answers combined spatial questions a paper map cannot.[1]

The world in layers land use plots roads contours Each layer links a place to its data; stack and combine them to ask new questions. 'GIS is just a digital map' is a myth — a map displays; a GIS ANALYSES place and data together.
DiagramA GIS holds the world in stacked layers — roads, plots, land use and contours — that can be combined

Place + data + analysis

A GEOGRAPHIC INFORMATION SYSTEM (GIS) captures, stores, analyses and displays data tied to LOCATION. Its core idea is that every feature has both a WHERE (geometry — a point, line or area on the earth) and a WHAT (attributes — a table of data about it), and a GIS links the two so you can MAP and ANALYSE them together. The world is held in LAYERS (themes) — roads, plots, land use, contours — that can be stacked and combined. MISCONCEPTION→correct: 'GIS is just a digital map' — a map only DISPLAYS; a GIS ANALYSES — it answers 'which plots within 500 m of a road are zoned residential and above the flood line?', which a paper map cannot.[1]

Display vs analyse A MAP displays a picture you look at it A GIS links place + data, analyses 'which plots near a road, residential, above the flood line?' you query it A paper map cannot answer a combined spatial question; a GIS can, in seconds. 'A map is objective truth' is a myth — every map is a projection, a selection and a classification.
DiagramA map only displays; a GIS links place to data and answers spatial questions a paper map cannot
Pinning data to a round earth the round earth (lat/long) the flat map (projected) distorts! Every projection distorts area, shape, distance or direction — choose it for the job. 'The projection doesn't matter' is a myth — mixing projections misaligns layers and corrupts every measurement.
DiagramYou cannot flatten the round earth onto a map without distorting area, shape, distance or direction
Overlays to software

History, systems & packages

GIS grew from the layered overlay (McHarg, 1969); it is a system of data, people and methods — and capable packages range from commercial ArcGIS to the free, open-source QGIS.[2, 3]

Overlays to software

GIS grew from a simple, powerful idea: the LAYERED OVERLAY. Planners and ecologists (notably Ian McHarg, 'Design with Nature', 1969) stacked transparent map layers on a light table to see where factors coincided; the first computer GIS (Canada GIS, the 1960s) automated exactly this. A modern GIS is a SYSTEM of hardware (computers, storage, digitizers, plotters, GPS), software, DATA (usually the costliest part), and people and methods. MISCONCEPTION→correct: 'GIS is the software' — like BIM, GIS is a system of data, people and methods; the software is one part, and the DATA is usually the largest investment.[2]

Map vs GIS

At a glance

AspectDetailNote
A mapDisplaysA picture
A GISAnalysesPlace + data, queryable
The world held asLayers / themesStacked and combined
ProjectionFlattens the sphereAlways distorts something
GIS isData + people + methodSoftware is one part; data costs most
Vocabulary

Key terms

GIS

A system that links place (geometry) to data (attributes) and analyses both.

Layer / theme

One kind of feature (roads, plots, land use) stacked with others.

Map analysis vs display

A GIS analyses and queries; a paper map only displays.

Coordinate system / projection

How features are pinned to the earth; flattening a sphere distorts.

Georeferencing

Tying a scanned map or image to real-world coordinates.

GIS packages

ArcGIS (commercial), QGIS (free, open-source), spatial databases.

Apply it

Lab task

Open QGIS (free) and load any two layers of your city (e.g. roads and wards). List three layers a planner would stack to study where new housing could go. Then write one spatial question that a GIS could answer but a paper map could not — and explain why the projection of your layers must match.

Check your understanding

Self-assessment

1. The key difference between a GIS and a digital map is that a GIS —

2. You cannot flatten the round earth onto a map without —

3. A capable, free and open-source GIS package is —

In a nutshell

Recap

A GIS links every place (geometry) to its data (attributes) and analyses both — it does not just display a map.
The world is held in layers (themes) that can be stacked and combined to ask new questions.
Automated cartography generates maps from data, but a map is always a projection, selection and classification — never neutral.
Coordinate systems pin data to the earth; you cannot flatten a sphere without distortion, so match projections carefully.
GIS is a system of data, people and methods; ArcGIS (commercial) and QGIS (free) are the standard packages.
The evidence

References & further reading

  1. [1]ESRI, Understanding GIS — what a GIS is, layers, coordinate systems and projections.
  2. [2]Ian McHarg, Design with Nature (1969) + the history of the layered overlay and early GIS.
  3. [3]QGIS / ArcGIS documentation — standard GIS packages and automated cartography.

Further reading

  • ESRI — Understanding GIS: The ArcGIS Method.
  • Maguire, Batty & Goodchild — GIS, Spatial Analysis and Modeling.
  • Ian McHarg — Design with Nature.

Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.