nr 322: single layer analysis jim graham fall 2008 chapter 8 & 9
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NR 322: Single Layer Analysis
Jim Graham
Fall 2008
Chapter 8 & 9
Geometric Calculations
Making Centroids
• Add fields for X and Y
• Use “Calculate Geometry” to add the X and Y coordinates of the centroid
• Open the dbf in Excel
• Save the dbf to a tab-delimited text file
• Use “Tools -> Add X Y Data” to add the text file as points
Buffering
• Creates polygons around existing vector features
Buffering
• Create a polygon Shapefile for buffers
• Open the “Editor” toolbar
• Start an edit session
• Select a feature using the edit tool
• Task: Create new feature
• Target: <your new shapefile>
• Select “Buffer” from the “Editor” menu
• Enter the distance for the buffer to add around the feature
Dissolving
• ArcToolbox -> Data Management Tools -> Generalization -> Dissolve
• Combines features based on a common attribute value
Clip
• ArcToolbox -> Analysis Tools -> Extract -> Clip
• ArcToolbox -> Overlay -> Erase
• ArcToolbox -> Data Management Tools -> Raster -> Clip
Intersection
• ArcToolbox -> Analysis Tools -> Overlay -> Intersect
• ArcToolbox -> Spatial Analysis Tools -> Local -> Combine
Generalization
• ArcToolbox -> Data Management Tools -> Generalization -> …
Generalization (100 meters)
Original Generalized to 100 meters
Generalization (1000 meters)
Original Generalized to 1000 meters