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

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

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

GIS maps consist of multiple layers

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

Types of Datasets Vector (feature) Point Polyline Polygon

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

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

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

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

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

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

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

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

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

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

Yeah!