[mapserver-users] optimize raster for mapserver - gdal geoTIFF source

[Mark Volz]

Hello,

I added a GeoTIFF to one of my .map files.  When zoomed in the image appears fine.  When I zoom out the image appears grainy, especially when looking at dirt fields.  I assume the problem is that I built the overviews with the wrong resampling method when I built overviews with gdaladdo.

Question 1)  Does anyone have any recommendations for resampling air photos when I create an image using gdal? {nearest (default),average,gauss,cubic,average_mp,average_magphase,mode}

Question 2) I am using a compressed geoTIFF with built in overviews.  I am happy with this format as the file size is small, and the speed is fast.  I am wondering if this is format for having a fast raster while keeping a relatively small file.  Does anyone else have any other suggestions?

Question 3)  I have seen several Mapserver snippets of code concerning GDAL_FORCE_CACHING and GDAL_ONE_BIGREAD.   If I am not reprojecting my imagery which processing directive(s) would be better for a compressed GeoTIFF with overviews?


LAYER
 ...
  PROCESSING "GDAL_FORCE_CACHING = YES"
 Or:
  PROCESSING "GDAL_ONE_BIGREAD = YES"
...
END # Air Photo Layer


Thank You

Mark Volz
GIS Specialist


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