1.4 Geographic Information Systems (GIS)

• Meaning and components of a Geographic Information System
• Spatial and attribute data
• Data capture: remote sensing, GPS, digitising and existing records
• Raster and vector data models
• Layers and overlay analysis
• Applications of GIS
• Advantages and limitations of GIS

• explain the meaning and components of a Geographic Information System
• distinguish spatial from attribute data
• describe methods of capturing geographical data for GIS
• explain how layers and overlay analysis are used to solve problems
• describe applications of GIS in day-to-day life
• appreciate the role of GIS in planning and decision making

“How would you decide where to build a new hospital?”

“What can a computer do with a map that a paper map cannot?”

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1. What GIS is and how it stores the world
   40 min · 1 practice tasks · quiz
   The components of a GIS, the two kinds of data it holds, and where that data comes from.
2. Layers, overlay analysis and what GIS is used for
   40 min · 2 practice tasks · quiz
   How stacking information answers real questions, and where GIS is already at work.
3. The five components of a GIS
   40 min · 1 practice tasks · quiz
   Hardware, software, data, people and methods, named in Kenyan workplaces rather than as a list to memorise.
4. Spatial data and attribute data
   40 min · 1 practice tasks · quiz
   Where a feature is, what it is like, and why joining the two is what a paper map cannot do.
5. Remote sensing as a GIS input
   40 min · 1 practice tasks · quiz
   Satellites and aerial photographs collect data without touching the ground; GIS is what you do with that data afterwards.
6. GPS, digitising and existing records
   40 min · 1 practice tasks · quiz
   Three other capture methods: fixing a point in the field, tracing Survey of Kenya paper, and joining tables already collected.
7. Raster and vector data models
   40 min · 1 practice tasks · quiz
   A grid of cells against points, lines and polygons, and why a Kenyan GIS keeps both.
8. Layers on Kenyan maps
   40 min · 1 practice tasks · quiz
   Switching layers on and off in an online map or on tracing paper, using Survey of Kenya themes as the stack.
9. Siting a hospital on the Nairobi fringe
   40 min · 1 practice tasks · quiz
   Overlay analysis applied to a real Kenyan siting problem: where a new hospital could go between Nairobi and Kiambu.
10. Buffers, queries and network analysis
    40 min · 1 practice tasks · quiz
    Three everyday GIS operations besides overlay, run on Kenyan rivers, schools and ambulance routes.
11. GIS in health, farming and disasters
    40 min · 1 practice tasks · quiz
    How overlay, buffers and queries are already used in Kenyan clinics, farms and flood plains.
12. GIS in counties, land and forests
    40 min · 1 practice tasks · quiz
    How Kenyan counties, the lands system and Kenya Forest Service use layers for planning and control.
13. Advantages, limits and GIS careers
    40 min · 1 practice tasks · quiz
    What GIS is good at, where it fails, why output can look too sure, and who gets paid to run it in Kenya.