I'm investigating the feasibility of using OSS as a tool to be used for
complying with the US-based Government Accounting Standards Board
Statement'34 (GASB-34) on improved financial accountability for state and
local governements. Particularly to assist in the section that covers
first time information about the government's public infrastructure
assets, such as bridges, roads, storm sewers, parks and rec facilities,
etc.
I'm curious if there are subscribers to this list familiar with GASB-34
that have either implemented, or are considering implementing any open
source GIS tools for asset tracking.
Furthermore, I'm looking for precedence in managing true community-based
development efforts to implement open source (in general) GIS/mapping
systems. Or to find out if there would be any interest in assisting with
such an initiative, however moderate involvement may be.
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,
Can I do this job by using GRASS?
If so, is there any free GIS data(?) on the Internet that I can use for my purpose to calculate the lake’s area?
If there are, what the process I will follow to get this work out?
Heartfully Thanks To You
Sincerely
Galip.Yasin
University of Tsukuba
Mater’s Program in Environmental Science
aderes: Japan, Ibaraki Province Tsukuba City
e-mail: s01k154@shako.sk.tsukuba.ac.jp
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.
Malte
Dear GRASS Users
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?
Heartfully Thanks To You
Sincerely
*********************************
Galip.Yasin
University of Tsukuba
Mater's Program in Environmental Science
aderes: Japan, Ibaraki Province Tsukuba City
e-mail: s01k154@shako.sk.tsukuba.ac.jp <mailto:s01k154@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.
Hamish
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?
On Fri, Jun 06, 2003 at 10:41:01AM -0600, Jack Varga wrote:
I'm investigating the feasibility of using OSS as a tool to be used for
complying with the US-based Government Accounting Standards Board
Statement'34 (GASB-34) on improved financial accountability for state and
local governements. Particularly to assist in the section that covers
first time information about the government's public infrastructure
assets, such as bridges, roads, storm sewers, parks and rec facilities,
etc.
I'm curious if there are subscribers to this list familiar with GASB-34
that have either implemented, or are considering implementing any open
source GIS tools for asset tracking.
Furthermore, I'm looking for precedence in managing true community-based
development efforts to implement open source (in general) GIS/mapping
systems. Or to find out if there would be any interest in assisting with
such an initiative, however moderate involvement may be.
I'm not familiar with GASB-34.
If you are looking for Free Software solutions or to coordinate
possible joing efforts, the website and mailinglist of the
FreeGIS-Project (www.freegis.org) is a good place to look.
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)
ok, I just tested this, thought I'd share the results.
(Summary: everything works fine, don't worry about it.)
At 10m resolution:
(r.report uses r.stats, so they have the same answer)
r.stats -a -n
10 36703800.000000
r.poly
d.what.vect
Area - Category 10
Size - Sq Meters: 36703600.000
other areas reported slightly under as well, but that may just be the
corners being cut off, in which case the vector area might more correct
anyway. It's very slight effect though.
I, may be failed on describe my problem correctly, which related to calculate a Lake’s area. So, please let me try to describe my problem more concretely.
I didn’t have any settllite image for my purpose.
Problem is:
Are there free settllite images on the internet which I can download and use at GRASS for calculate lake’s area?
Note: my research lake’s area is around 500 km2 or so,
approximately in E82, E84, N44, N46, in China’s Uighur Autonomous Region.