This example uses the 21 Land Use Category Theme and the finalpoly.shp file created using the Watershed Delineation by Point MassGIS Watershed Analyst tool

First, add the land use theme and create the finalpoly.shp file using the MassGIS Watershed Analyst.

Now that you have your themes there are two steps to clipping:

1. Cut your land use theme using the finalpoly.shp theme as the “cookie cutter”.
2. Recalculate the land use areas because the polygons along the edges of the cookie cutter will be slightly inaccurate. 

1. Go to File – Extensions, and add the Geoprocessing extension.
2. Go to View – Geoprocessing Wizard

a. Click on “Clip one theme based on another”, then next.
b. The input them to clip is the theme you want clipped (Land Use in this case).
c. The “polygon overlay theme” is the cookie cutter (finalpoly.shp in this case).  
d. The output file can be named anything.  
e. Click on Finish.  
f. You now have a “clipped” theme in one solid color.

3. In order to change the colors to the original color scheme, do this:

a. Double click on the original theme (land use).
b. Click Save to save the legend.
c. Choose a name to save the legend as.
d. Close the original themes Legend Editor.
e. Double click on the new shape file theme.
f. Click load in the Legend Editor.
g. Load the file name you saved the original as.
h. Click apply in Legend Editor.
i. You can now uncheck the original theme in the data viewer.

1. Make the new shape file (clip1.shp) active.
2. Go to Theme – Calc Geometry

a. Yes to Update Area
b. Yes to Update Perimeter

3. Open the Theme Table for your shape file (clip1.shp).  

a. There are now three buttons on the upper right

i. Summarize Land Use
ii. NPS Loads
iii. % Impervious

b. Use these buttons to print your statistics!

Last Updated 6/12/2002
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