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<DIV><FONT face="MS UI Gothic">Hello Hamish,</FONT><FONT face="MS UI Gothic">
Malte & GRASS users</FONT></DIV>
<DIV><FONT face="MS UI Gothic"></FONT> </DIV>
<DIV><FONT face="MS UI Gothic">Firstly, thank you very much for your
help.</FONT></DIV>
<DIV><FONT face="MS UI Gothic">My second problem is I didn't have any
source data.</FONT></DIV>
<DIV><FONT face="MS UI Gothic">So I am longer for your
advice for:</FONT></DIV>
<DIV><FONT face="MS UI Gothic"> 1, Could I get some free spatioal data on
the Internet, which, as a source data, I can use in </FONT><FONT
face="MS UI Gothic">GRASS for my purpose ( to calculate the
area)?</FONT></DIV>
<DIV><FONT face="MS UI Gothic" size=1></FONT> </DIV>
<DIV><FONT face="MS UI Gothic">Sencerely</FONT></DIV>
<DIV><FONT face="MS UI Gothic"></FONT> </DIV>
<DIV><FONT face="MS UI Gothic" size=2>Alipu Yasen</FONT></DIV>
<DIV><FONT face="MS UI Gothic"
size=2>*********************************<BR>University of Tsukuba, Ibaraki Prov,
Japan<BR>e-mail: <A
href="mailto:s01k154@shako.sk.tsukuba.ac.jp">s01k154@shako.sk.tsukuba.ac.jp</A><BR>*********************************<BR>
</FONT></DIV>
<DIV>
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<DIV>>note d.what.vect reports area statistics as well; has anyone compared
the<BR>>answers from that with that of:<BR>>r.report
units=me<BR>>r.stats -a<BR>>?<BR>>(for a suitably high resolution
raster of course)<BR>>Additionally, there is r.surf.area for 3D (instead of
plan) surface<BR>>areas which may be more useful for steep terrain, but
introduces the<BR>>fractal problem and apparently suffers from underreporting
edge data as<BR>>well.<BR>>there is r.volume to look at as
well.<BR>>> of course you can do that. You just have to digitize the
lakeborder or<BR>>> get it from another source (e.g. arial photo) and
export it to a<BR>> >raster map. with the help of r.report you'll
get the area of the<BR>> >lake. to spare computing time I would mask the
area out. i'm not quite<BR>> >shure if v.area does the trick for vector
maps.<BR>> > <BR>> > > I want to calculate one lake's
yearly area change at the time scale<BR>> > >which may be from 1980 to
now. ( Ibnur Lake which located <BR>> > >approximately in E82, E84,
N44, N46, in China's Uighur Autonomous<BR>> > >Region). And my problem
is,<BR>> > >1. Can I do this job by using GRASS?<BR>>
> > 2. If so, is there any free GIS data(?) on the Internet
that I can<BR>> > > use for my purpose to calculate the
lake's area?<BR>> > > 3. If there are, what the process I
will follow to get this work<BR>> > > out?<BR></DIV></BODY></HTML>