[GRASSLIST:2622] Re: r.out.tiff

Eric G. Miller egm2 at jps.net
Wed Oct 31 12:27:59 EST 2001

On Wed, 31 Oct 2001 15:09:34 +0100, Heiko Kehlenbrink <heiko.kehlenbrink at vermes.fh-oldenburg.de> wrote:

> Hi all!
> Got some question about the r.out.tiff Command.
> I think since GRASS 5.0.0.pre2 there is a new flag  r.out.tiff -l  wich
> builds a tiled .tiff file.
> - does that flag cut the image in bunch of tiles so that a programm like
> gimp or mapserver are able to load parts of the data?
> - how big are those tiles hidden in the .tiff file?
> - could those tiled .tiffs be used in mapserver directly? (maybe this
> ones for you frank  ,-) )

Tiles are merely a layout format for TIFF's.  Currently, tiles are written
at 128x128 pixels.  For programs that can utilize tiles, it can help speed
up some drawing operations.  Better compression may also be achieved in
some cases.  It has little relationship to tiling map areas (it's merely a
file format option).

If you want to tile map areas, you probably want a tiff for each tile
region and some kind of naming or other convention.  For instance,
the USGS uses coded file names like 'O34098A5.[whatever]' to indicate
a file at 34N, 98W and "tile/quarter quad" "A5".

Eric G. Miller <egm2 at jps.net>

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