[GRASSLIST:333] Re: How can I do for getting a lake's area?

[Alip.Yasin]

Hello Hamish, Malte & GRASS users

Firstly, thank you very much for your help.
My second problem is I didn't have any source data.
So I am longer for your advice for:
  1, Could I get some free spatioal data on the Internet, which, as a source
data, I can use in GRASS  for my purpose ( to calculate the area)?

Sencerely

Alipu Yasen
*********************************
University of Tsukuba, Ibaraki Prov, Japan
e-mail: s01k154 at shako.sk.tsukuba.ac.jp
*********************************

>note d.what.vect reports area statistics as well; has anyone compared the
>answers from that with that of:
>r.report units=me
>r.stats -a
>?
>(for a suitably high resolution raster of course)
>Additionally, there is r.surf.area for 3D (instead of plan) surface
>areas which may be more useful for steep terrain, but introduces the
>fractal problem and apparently suffers from underreporting edge data as
>well.
>there is r.volume to look at as well.
>> of course you can do that. You just have to digitize the lakeborder or
>> get it from another source (e.g. arial photo) and export it to a
> >raster map.  with the help of r.report you'll get the area of the
> >lake. to spare computing time I would mask the area out. i'm not quite
> >shure if v.area does the trick for vector maps.
> >
> > > I want  to calculate one lake's yearly area change at the time scale
> > >which may be from 1980 to now. ( Ibnur Lake which located
> > >approximately in E82, E84, N44, N46, in China's Uighur Autonomous
> > >Region). And my problem is,
> > >1. Can I do this job by using GRASS?
> > >  2. If so, is there any free GIS data(?) on the Internet that I can
> > >   use for my purpose to calculate the lake's area?
> > >  3. If there are, what the process I will follow to get this work
> > > out?
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