Hi!
Is it possible to do an interpolation of points to a surface by fitting
the points to a first or second degree equation with GRASS or any other
program?
--W
On Tue, 15 Nov 2005, Wolf Bergenheim wrote:
Hi!
Is it possible to do an interpolation of points to a surface by fitting
the points to a first or second degree equation with GRASS or any other
program?
You can use gstat with GRASS to fit a trend surface to points and predict
a surface, see Neteler and Mitasova (2nd edition) Open Source GIS: A
GRASS GIS Approach, pp. 328-333 for GRASS 5, and notes on
http://www.gstat.org/grass.html for GRASS 6. You will find that the d=
argument sets the trend order degree.
--W
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand@nhh.no
You can also use R satistical language, to fit a trend surface up to 6th order.
check out this paper:
GROHMANN, C. H., 2005. Trend-surfaces analysis of morphometric
parameters: A case study in southeastern Brazil.
Computers & Geosciences, 30 (8):1005-1014.
grabe it here: http://www.igc.usp.br/pessoais/guano/downloads/Grohmann_CAGEO_2005.pdf
cheers
Carlos
On 11/15/05, Roger Bivand <Roger.Bivand@nhh.no> wrote:
On Tue, 15 Nov 2005, Wolf Bergenheim wrote:
> Hi!
>
> Is it possible to do an interpolation of points to a surface by fitting
> the points to a first or second degree equation with GRASS or any other
> program?
>You can use gstat with GRASS to fit a trend surface to points and predict
a surface, see Neteler and Mitasova (2nd edition) Open Source GIS: A
GRASS GIS Approach, pp. 328-333 for GRASS 5, and notes on
http://www.gstat.org/grass.html for GRASS 6. You will find that the d=
argument sets the trend order degree.> --W
>--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand@nhh.no
--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________
"Good morning, doctors. I have taken the liberty of removing Windows
95 from my hard drive."
--The winning entry in a "What were HAL's first words" contest judged
by 2001: A SPACE ODYSSEY creator Arthur C. Clarke
Not sure if this is what you're looking for, but v.sur.rst and v.surf.idw might help.
-Ian
On Nov 15, 2005, at 1:07 AM, Wolf Bergenheim wrote:
Hi!
Is it possible to do an interpolation of points to a surface by fitting
the points to a first or second degree equation with GRASS or any other
program?--W
>
What happens if a big asteroid hits Earth? Judging from realistic simulations involving a sledge hammer and a common laboratory frog, we can assume it will be pretty bad.
- Dave Barry
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Hi, again.
Following Markus Neteler's excelent R GRASS tutorial I've been able to
import some GRASS (vector) point data into R and I've been able to
interpolate the data. Now I'd like to be able to get the data back into
grass to be able to make a nice map of the interpolated data. But I
can't seem to find any advise on how to do it. Is it even possible?
I have an object ws.tmean_tr1 which is
str(ws.tmean_tr1)
List of 3
$ x: num [1:132] 2866517 2874825 2883133 2891441 2899749 ...
$ y: num [1:132] 6538650 6548635 6558619 6568604 6578589 ...
$ z: num [1:132, 1:132] -6.52 -6.57 -6.63 -6.68 -6.73 ...
x is the E-W coordinate, y is the N-S cordinate and z is the
interpolated temperature. How can I make this into a GRASS raster
map?
The only other reference I found was this:
http://grass.itc.it/pipermail/statsgrass/2005-August/000287.html, but
I'm not able to parse that info into my case. Please help!
--W
--
|Humpty Dumpty sat on a wall
(o< --|Humpty Dumpty had a great fall
//\ |All the king's horses and all the king's men
V_/_ |Couldn't put Humpty together again.
Wolf Bergenheim
Depends on the version of GRASS you are working on. If you are using one of the
5.x versions try with
library(GRASS)
g <- gmeta()
?sites.put # see help
Then rasterize (s.to.rast).
If you are using one of the 6.x versions try with
library(spgrass6)
g6<-gmeta6()
?putSites6 # see help
Then rasterize with v.to.rast.
Miha
--- Wolf Bergenheim <wolf+grass@bergenheim.net> wrote:
Hi, again.
Following Markus Neteler's excelent R GRASS tutorial I've been able to
import some GRASS (vector) point data into R and I've been able to
interpolate the data. Now I'd like to be able to get the data back into
grass to be able to make a nice map of the interpolated data. But I
can't seem to find any advise on how to do it. Is it even possible?I have an object ws.tmean_tr1 which is
>> str(ws.tmean_tr1)
List of 3
$ x: num [1:132] 2866517 2874825 2883133 2891441 2899749 ...
$ y: num [1:132] 6538650 6548635 6558619 6568604 6578589 ...
$ z: num [1:132, 1:132] -6.52 -6.57 -6.63 -6.68 -6.73 ...x is the E-W coordinate, y is the N-S cordinate and z is the
interpolated temperature. How can I make this into a GRASS raster
map?The only other reference I found was this:
http://grass.itc.it/pipermail/statsgrass/2005-August/000287.html, but
I'm not able to parse that info into my case. Please help!--W
--
|Humpty Dumpty sat on a wall
(o< --|Humpty Dumpty had a great fall
//\ |All the king's horses and all the king's men
V_/_ |Couldn't put Humpty together again.Wolf Bergenheim
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