[GRASS-user] Determine surface areas

[Nikolaus Arnold]

Hi!

I am new to using GIS and GRASS.
I am currently working on a task where I have to determine the type of 
surface around a specific coordinate. For example what is the total 
water surface area in a 100km radius around the Eiffeltower.
I have found a landcover map ( 
http://glcf.umiacs.umd.edu/data/landcover/ ) with a 1km raster that 
isn't perfect but should do the job. After some time I managed 
displaying the map and showing only specific values in GRASS. My next 
step would have been exporting the map to an image, draw the desired 
circles with a image editing tool and count the contained fields manually.
But taking a closer look at GRASS and the vectormap function, I wondered 
if it would be possible to create vector circles, merge them with the 
existing map and let GRASS do the work of counting the Areas.

Does this seem possible? If yes, what would be the first steps?

Any help would be very much appreciated
Kindest regards
Nikolaus