[GRASS-user] r.patch

GRASS GRASS user
1

Hello,

I want to combine a lot of tiles to a big image. I tried to use r.patch but it is quite slow. It needs about 2-3 h for 100 tiles of the size 2000x2000 cells. The images are fit exactly to the neighbours (no overlay, no gap). Is there a better (and faster) way to join the graphics?

Thanks
Wolfgang

2

WolfgangZillig wrote:

I want to combine a lot of tiles to a big image. I tried to use r.patch
but it is quite slow. It needs about 2-3 h for 100 tiles of the size
2000x2000 cells. The images are fit exactly to the neighbours (no
overlay, no gap). Is there a better (and faster) way to join the graphics?

gdalwarp

3

Maciej Sieczka schrieb:

WolfgangZillig wrote:

I want to combine a lot of tiles to a big image. I tried to use r.patch
but it is quite slow. It needs about 2-3 h for 100 tiles of the size
2000x2000 cells. The images are fit exactly to the neighbours (no
overlay, no gap). Is there a better (and faster) way to join the graphics?

gdalwarp

do you have a minimal example? Neither gdalwarp --help nor http://www.remotesensing.org/gdal/gdalwarp.html explain how I can feed several images into gdalwarp.

Wolfgang

4

WolfgangZillig wrote:

Maciej Sieczka schrieb:

gdalwarp

do you have a minimal example? Neither gdalwarp --help nor
http://www.remotesensing.org/gdal/gdalwarp.html explain how I can feed
several images into gdalwarp.

First create a raster to store all your input rasters, then put them
there. Why not try looking for the answer in the mailing lists archive
before asking a question?

Maciek

5

I just figured out that I did an error while downloading the data. So I just did a rm *.*

Perhaps I will ask the question in a few days again ;-(

6

Wolfgang,

I realize that there has already been some give and take on this, but wanted
to point out some numbers.

Each 2000x2000 cell tile has 4,000,000 cells.

100 of these represent 400,000,000 cells to merge.

This quite a lot. So depending on the systems you have (processor speed,
total RAM, hard drive capacity and speed), this may be pretty reasonable.

Michael

On 12/14/06 8:26 AM, "WolfgangZillig" <wollez@gmx.net> wrote:

Hello,

I want to combine a lot of tiles to a big image. I tried to use r.patch
but it is quite slow. It needs about 2-3 h for 100 tiles of the size
2000x2000 cells. The images are fit exactly to the neighbours (no
overlay, no gap). Is there a better (and faster) way to join the graphics?

Thanks
Wolfgang

__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

7

Maciej Sieczka schrieb:

WolfgangZillig wrote:

Maciej Sieczka schrieb:

gdalwarp

First create a raster to store all your input rasters, then put them
there. Why not try looking for the answer in the mailing lists archive
before asking a question?

I found perhaps a better way to do it. I just had to search some mailing lists ;-))

Wolfgang