I need to get the length and area of some landscape features in the US. My data was in lat and long degrees. I created a new location with an UTM projection and read the data into grass.

Now if I use the measure distance tool in the Map Display it appears in degrees. If I make a new column in the attribute table and then calculate the area, I also am not able to get something like square miles or kilometers.

Any suggestions ?


It depends on the location projection (UTM in meters), not on the shapefile projection (in degrees) and GRASS GIS does not allow reprojection on the fly (look at GRASS wiki: Map Reprojection)

You need to:

1) first create a location in the projection of your shapefile (in degrees)
2) import the shapefile into this location
3) within your new location (UTM), use v.proj to reproject the layer from the import location to the destination location.

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