[GRASS5] Re: [GRASSLIST:2842] import raster

Frank Warmerdam warmerdam at pobox.com
Fri Mar 5 10:33:05 EST 2004

> On Thu, Mar 04, 2004 at 04:55:44PM +0100, Daniele Scarselli wrote:
>>I've a problem importing some raster:
>>I use r.in.gdal to import a raster and the results are files over 100 mb for 
>>every raster.
>>With r.compress I reduce to 17,4 mb.
>>Is there a method to reduce again these files?
>>I think that GRASS take the raster as a 8 bit image while the original is 
>>black and white (1 bit)
>>Daniele Scarselli

Markus says:
> Anything to improve in r.in.gdal (we all like small files)?

Daniele / Markus,

If you are reading a 1bit file, it will usually be treated as byte data by
the GDAL (depends on the driver).  Byte data is written as integer cells.
I don't think there is anything else that would be appropriate.

I am curious what r.compress does that is special?  Don't grass rasters normally
get compressed as they are written?  Are import programs supposed to write
them compressed?  It may be that the steps taking ... import and then compress
are normal practice?

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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