🎯 Learning Objectives
- Derive new surfaces from a DEM (Slope, Aspect).
- Calculate Euclidean Distance from vector features.
- Reclassify different data types into a common scale (1-10).
- Perform a Weighted Overlay to combine factors into a final suitability map.
🧪 Interactive Tool: Map Algebra Playground
Raster analysis is just math. Use this tool to add two grids together pixel-by-pixel before trying it in Pro.
📂 Scenario: The New Fire Station
The city needs to build a new fire station in the mountains. You have been tasked with finding the best site based on three criteria:
- Slope: Must be flat (flatter is better).
- Road Access: Must be close to existing roads (closer is better).
- Land Cover: Must not be on water or protected forest.
lab06_suitability.zip
Contains: DEM.tif, Roads.shp, LandUse.tif
🛠️ Step-by-Step Instructions
Select your preferred GIS platform to view instructions:
Derive Surfaces
1. Open Geoprocessing > Slope.
2. Input: DEM.tif.
3. Output: Slope_Map.
4. Run. The output shows steepness in degrees.
Euclidean Distance
1. Search for Euclidean Distance (Spatial Analyst).
2. Input: Roads.shp.
3. Output: Distance_Roads.
4. Run. The output is a raster where every pixel value is the distance to the nearest road.
Reclassify
We need to compare "Degrees of Slope" (0-90) with "Meters of Distance" (0-5000). To do this, we reclassify both to a 1-10 scale.
1. Reclassify tool.
2. Input: Slope_Map.
3. Remap: 0-5 deg = 10 (Best), >30 deg = 1 (Worst).
4. Repeat for Distance_Roads (0-100m = 10, >1000m = 1).
Weighted Overlay
1. Search for Weighted Overlay.
2. Add your Reclassified Slope and Reclassified Distance layers.
3. Assign weights (e.g., Slope 50%, Roads 50%).
4. Run. The result is your final Suitability Map.
✅ Submission & Assessment
To complete this lab, you must submit:
- Suitability Map: Color-coded from Red (Bad) to Green (Good).
- Site Recommendation: Identify one specific area (lat/long) that has a score of 9 or 10.
- Written Justification: Why did you choose the weights you did? (e.g. Is slope more important than road access?)