[mapserver-users] pyramid, .rrd file

[Frank Warmerdam]

Berényi Attila wrote:
> Dear All,
> 
> Is there any possibility to use ERDAS .rrd file in Mapserver focusing on 
> the pyramid function?
> A bit detailed information: I have a lot of georeferenced orthophotos 
> and I'm looking for the best way it display them via Mapserver as fast 
> and as detailed as possible.
> I've tried gdal_retile, but it's slow, and I don't really understand how 
> it works...
> Any suggestion would be very much appreciated!

Attila,

Generally speaking Mapserver should already take advantage of .rrd
pre-built overviews.  If you want to confirm if GDAL (and consequently
MapServer) can see the overviews, run the gdalinfo utility on the base
file, and check the report of the individual bands to see if they have
an overviews list.

For example

gdalinfo image_col.img
...
Band 1 Block=64x64 Type=UInt16, ColorInterp=Undefined
   Description = Layer_1
   Min=232.000 Max=1024.000
   Minimum=232.000, Maximum=1024.000, Mean=335.990, StdDev=26.558
   NoData Value=65535
   Overviews: 692x600, 345x299, 171x148, 84x73, 41x35
...

This file has an .rrd ith 5 overview levels and they would be used
by MapServer as long as the .rrd file is kept with the .img file.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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