[GRASS-user] One raster from many

GRASS GRASS user
1

Daniel Farnan @ San Francisco wrote:

Tried r.patch and r.cross - did not use these previously, r.patch
took over 4 days to process the rasters, and still crashed my
machine.

It's better to reply via the mailing list, so more folks can participate.

r.patch should not fail to process as little as 11 SRTM tiles within 4
days, either 1" or 3". Propably you have your working region/resolution
set to big and running out of memory?

try:

g.region rast=rast1,rast2,...,rast11 -a
r.patch in=rast1,rast2,...,rast11 out=rast_all

Does that still crash? What GRASS version and platform?

I am not really concerned about the null values,

No worries. r.patch will treat null transparent.

the area
is large, and the files had to be downloaded piecemeal from USGS, I
just want to put them together as one file. :slight_smile: thanks for the
response - I was hoping it was r.patch when I did the GUI
exploration last week, however it seems not.

Besides r.patch (and multipurpose r.mapcalc) there is not other tool in
GRASS usefull for "quilting" rasters I guess.

Maciek

2

Worked much faster than 4 days, but generated a blank (white) raster.
- this may be due to the srtm data(?). All were imported as .tif with
r.in.gdal.
I know I had done this another way initialy, as I said, similar to
resetting the region when subsetting a raster map, I just cannot recall
what I did.
(sorry Maciek, I sent too quickly - meant to include the list).
-----Original Message-----
From: Maciej Sieczka [mailto:tutey@o2.pl]
Sent: Monday, July 16, 2007 11:33 AM
To: Daniel Farnan @ San Francisco
Cc: GRASSLIST
Subject: Re: [GRASS-user] One raster from many

Daniel Farnan @ San Francisco wrote:

Tried r.patch and r.cross - did not use these previously, r.patch took

over 4 days to process the rasters, and still crashed my machine.

It's better to reply via the mailing list, so more folks can
participate.

r.patch should not fail to process as little as 11 SRTM tiles within 4
days, either 1" or 3". Propably you have your working region/resolution
set to big and running out of memory?

try:

g.region rast=rast1,rast2,...,rast11 -a
r.patch in=rast1,rast2,...,rast11 out=rast_all

Does that still crash? What GRASS version and platform?

I am not really concerned about the null values,

No worries. r.patch will treat null transparent.

the area
is large, and the files had to be downloaded piecemeal from USGS, I
just want to put them together as one file. :slight_smile: thanks for the
response - I was hoping it was r.patch when I did the GUI exploration
last week, however it seems not.

Besides r.patch (and multipurpose r.mapcalc) there is not other tool in
GRASS usefull for "quilting" rasters I guess.

Maciek

3

Daniel wrote:

> I was hoping it was r.patch when I did the GUI
> exploration last week, however it seems not.

It's the one you want.

Maciej wrote:

g.region rast=rast1,rast2,...,rast11 -a
r.patch in=rast1,rast2,...,rast11 out=rast_all

Daniel Farnan wrote:

Worked much faster than 4 days, but generated a blank (white) raster.
- this may be due to the srtm data(?). All were imported as .tif with
r.in.gdal.

probably just the color map. Try r.info and r.univar to see that the
raster contains some data, then 'r.color color=srtm' or similar.

Hamish