1 Definition of GIS
A Geographic Information System (GIS) is a computer-based tool designed to capture, store, manipulate, analyse, manage, and present spatial or geographic data. It links where things are with what things are like.
- Handles both spatial data (location — coordinates, geometry) and non-spatial / attribute data (characteristics — name, population, type).
- Think of it as a smart map that can query, analyse, and model real-world phenomena.
2 Components of GIS
- Hardware: Computers, GPS receivers, digitisers, plotters, servers.
- Software: ArcGIS, QGIS, GRASS GIS, PostGIS.
- Data: Spatial (vector/raster) and attribute (tables).
- People: Analysts, developers, decision-makers.
- Methods/Procedures: Workflows, standards, analysis techniques.
3 Features and Functions of GIS
- Data Input: Digitising, scanning, GPS import, remote sensing.
- Data Storage: Geodatabases, shapefiles, raster formats.
- Data Manipulation: Projection, transformation, editing.
- Data Analysis: Overlay, buffer, proximity, network analysis.
- Data Output: Maps, charts, reports, web services.
4 Four Ms of GIS
- Measurement: Distance, area, perimeter calculations.
- Mapping: Thematic maps, choropleth maps, cartographic output.
- Monitoring: Change detection, temporal analysis.
- Modelling: Suitability analysis, simulation, prediction.
5 Importance and Applications
GIS enables spatial decision-making across virtually every discipline.
- Urban planning: Zoning, land-use mapping, infrastructure.
- Environmental management: Deforestation monitoring, pollution tracking.
- Disaster management: Flood modelling, evacuation planning.
- Civil engineering: Route selection, cut-fill analysis, site suitability.
- Agriculture: Precision farming, crop health monitoring.
- Public health: Disease outbreak mapping, facility siting.
6 GIS vs Cartography, CAD, and DBMS
| Aspect | GIS | Cartography | CAD | DBMS |
|---|---|---|---|---|
| Primary purpose | Spatial analysis | Map making | Design/drafting | Data management |
| Topology | Yes | No | No | No |
| Attribute data | Linked to geometry | Limited | Minimal | Rich but non-spatial |
| Analytical capability | Extensive | None | Basic | Non-spatial queries |
7 GIS Data Feeds
- Topographic maps and survey data.
- GPS observations.
- Remote sensing / satellite imagery.
- Census and statistical databases.
- Field surveys and ground-truth data.
- Existing digital databases and scanned documents.
8 Historical Development
- Pre-1960s: Manual cartography, transparent overlay analysis (Ian McHarg).
- 1960s: Canada Geographic Information System (CGIS) — Roger Tomlinson.
- 1970s–80s: ESRI founded (1969); ARC/INFO released (1982).
- 1990s: Desktop GIS (ArcView, MapInfo); GPS civilian access.
- 2000s: Google Earth (2005), open-source GIS (QGIS, PostGIS).
- 2010s–present: Cloud GIS, mobile mapping, AI in spatial analysis.
Definition + list all 5 functions (input, storage, manipulation, analysis, output). Draw a block diagram showing real world represented as stacked GIS layers.
Five components: Hardware, Software, Data, People, Methods. Explain each briefly with examples. Draw a diagram with GIS at centre connected to all five.
Spatial: Data with location — coordinates, geometry (point for well, line for road, polygon for district). Non-spatial: Descriptive attributes — name, population, elevation. In GIS these are linked.
Measurement, Mapping, Monitoring, Modelling. Give one application example per M.
Route planning, site suitability, flood modelling, cut-fill analysis, land-use mapping, infrastructure management. Emphasise spatial decision-making.
Use a comparison table. Key: GIS has topology and analytical capability; Cartography is static; CAD lacks attribute linkage.
Maps, GPS, remote sensing, census/statistics, field surveys, digitised documents. Explain how each feeds data into the system.
Key milestones: CGIS (1960s), ARC/INFO (1982), Desktop GIS (1990s), Google Earth (2005). Mention Roger Tomlinson as "Father of GIS."