1. Emma Gildesgame, Katie Lebling and Ian McCullough
Watershed/GIS
Emma Gildesgame, Katie Lebling and Ian McCullough

2. What is GIS? Geographic Information System ArcGIS 9.3.1 Manny Gimond
ArcMap
ArcCatalog
Manny Gimond
Master of GIS

3. What does GIS do? Map generation Spatial analysis
Data storage and organization
Modeling

4. GIS maps consist of multiple layers

5. Types of Datasets Raster Made of pixels
Each pixel has a numerical value
Cellsize (resolution) can be adjusted

6. Types of Datasets
Vector (feature)
Point
Polyline
Polygon

7. Attribute Tables
Layers have attributes, which are basically data attached to each layer
Each polygon can have several fields (columns)

8. Types of Datasets Image files Scanned Oakland tax map (jpg)
Digital orthophotoquad (for land use digitizing)

9. Models to be Generated Erosion potential Erosion impact
Septic suitability
Development impact
Phosphorus

10. How to build a model
Modeling erosion potential in the Belgrade Lakes region
Input variables
Soil
Slope
Land use

11. How to build a model Convert vector land use data to raster
Reclassified raster
Vector
Raster
Each land use type has an erosion potential rating of 0-9

12. How to build a model Convert vector soil data to raster Vector Raster
Reclassified K-factor
Reclassified K-factors on scale of 1-7
Reclassified K-factor = 11.6Kf +1

13. How to build a model Slope data already is a raster! Slope raster
Convert to percentages
Reclassified on scale of 1-9
But it still needs to be reclassified

14. How to build a model Multiply raster values by variable weight
Soil K-factor: 40%
Slope: 30%
Land use: 30%
Soil
Slope
Land use
For example, the soil raster values were all multiplied by 0.4, to reflect the 40% weighting in the model

15. How to build a model
Add up the weighted variables with the Raster Calculator in Spatial Analyst

16. Higher cell values indicate higher erosion potential
Voila
Higher cell values indicate higher erosion potential

17. Yeah!