[GRASS-user] Determine surface areas

[achim]

Hi,

one possibility is:

1) create vector-map with Eiffeltower-coordinate as point
2) v.buffer
3) v.to.rast ... => "eiffelbuffer"
4) r.mask ("eiffelbuffer")
5) r.mapcalc ... "watercells" if (landcover==water,1,null())
6) r.sum rast="watercells"

for (exact) syntax please read the manuals.

If any problems occur, just tell.

Hope I could help,

Achim

Nikolaus Arnold schrieb:
> 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
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