[GRASSLIST:221] Re: Tiled Tiffs

[Richard Greenwood]

At 10:28 AM 5/27/2003 -0400, you wrote:

>At 7:46 PM +0100 2003/05/23, Glynn Clements wrote:
>>R. Sean Fulton wrote:
>>
>>>  Are there any simple instructions anywhere for outputting tiled Tiffs
>>>  with Grass?
>>
>>"r.out.tiff -l ..." generates tiled TIFFs (128x128 tiles).
>>
>>--
>>Glynn Clements <glynn.clements at virgin.net>
>
>I've tried this and I only get one TIFF. Is this correct behavior? I was 
>under the impression that it would create multiple files -- one for each tile.
>
>Also, can Grass create an index shape file for the tiles.
>
>Thanks.
>
>         Sean Fulton

The word 'tiled' refers to the internal data structure of the tiff file. 
Tiff can be structured in a lot of ways: stripped, monolithic, tiled, LZW 
compressed, etc. There are compatibility and performance issues with the 
various formats.

Sounds like what you want is sort of a reverse 'r.patch'. I am not aware of 
any automated routine for this in GRASS, but a bit of shell scripting 
should get you what you want. Maybe create a polygon grid of the desired 
output tiles. The v.extract one tile at a time, and v.to.rast ... out=MASK, 
then r.out.tiff. Actually, you could just set your region before running 
r.out.tiff and get the same effect.

Also you might want to look at gdal_translate, 
http://www.remotesensing.org/gdal/index.html which has the ability to read 
GRASS files and output cropped tiff's, but it would require a similar 
amount of scripting in order to automate the process.

Rich


Richard W. Greenwood, PLS
Greenwood Mapping, Inc.
Rich at GreenwoodMap.com
(307) 733-0203
http://www.GreenwoodMap.com