Census coverage

[Chris C Rewerts]

>From grass-lists-owner at max.cecer.army.mil Thu Nov 19 19:38:03 1992
>
>Hello,
>
>What's the best way to get external vector files into GRASS raster
>so that they can be overlayed?  I want to know the population inside
>of a polygon.  I'm starting with ascii counts by tract, the tract
>in TIGER boundaries,  and x,y(UTM) for the polygon.  How do you fill
>a polygon?  I can probably create the raster files in "C", but is 
>there a way using GRASS commands? 
>
>Thank you.
>

If I read this correctly, you have vector maps with tract polygons
tagged with with populations, and you want to convert the vector map
to raster format so you can do overlay operations. 

If the polygons are areas (not lines) in the vector map, then you 
can use the v.to.rast program to create raster maps.  In the 
resulting raster map, the cells in the areas inside the polygons
will all be given the category value of the original polygon from
the vector map.

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Chris Rewerts        rewerts at ecn.purdue.edu
Agricultural Engineering, Purdue University