[GRASSLIST:1389] Re: why r.report gives wrong figured area data?

[Alip.Yasin]

Dear Sir Hamish, Nathaniel Vaughn Kelso

Thank you for your help.
I tried several times by following  Mr.Hamishs advice.
 >g.region rast=map_name
 >will zoom to the extent of the map, and to the map's resolution.
 >Also try using 'd.barscale' to make sure the map scale it correct.
 >If you used v.digit to mark the outline of the lake you could use
 >'d.what.vect' to query the area too.

But still got the same results.
So I am going to accepte Nathaniel Vaughn Kelsos advice,
and multiply the resultes by 1000 and uses those as my area data.
But still want to know what caused this kind of problem.

If any one knows about this, Please, give me some advice.
Heartfully Thanks.
Sincerely
Ghalip Yasin

My Problem:
> I " i.rectify"ed and got several different seasons map in target XY
> location, and "r.digit"ed a lake area respectivly.
> After these I entered command "r.report" for each map and see the results.
> It goes very pretty and gives me following results.
> For map2 (2001.09.25): 1/lake area...0.623 km^2
> For map1 (2002.10.30): 1/lake area...0.928 km^2
> For map3 (2003.05.25): 1/lake area...1.125 km^2
> But the problem is the results were much smaller than the real area.
> The real area of this lake was changed from 500km2 to 1200km2 in these 5
years.
> So my question is: why r.report gives me the wrong figured area data?



-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/grass-user/attachments/20031001/17f1100b/attachment.html