Interpolate image

[Pål Kristensen]

Hi!

After reading history.txt of MS 5.0 Final I found out that this issue
actually was a bug (ticket 2303) that was solved from RC2 to final release.
I was also not aware of the PROCESSING "RESAMPLE=BILINEAR" statement that
applies to a raster layer. This statement does exactly what I tried to
accomplish, so thanks for the help.

Regards,
Pål



Pål Kristensen wrote:
> 
> Hi!
> 
> I have recently installed ms4w 2.2.6 beta which include MS 5.0 RC2. The
> reason for this was to test the new AGG rendering engine when using
> Mapserver as a WMS server, with only high resolution (RGB) rasters as the
> data source. Most WMS servers around (both free and commercial) uses
> nearest neighbor interpolation on the resulting image that is transfered
> to the client. In situations where the source data is only hires rasters
> or imagery (as in my case), the quality of the output would be much better
> if you could apply an bilinear interpolation to the produced image (see
> the attached images for an example). Because in most cases the pixels in
> the source data and the pixels on the screen do not match up, even if I
> have produces pyramids on the source data (using gdal gdaladdo with the
> average option sett). The only WMS servers that has the ability to
> interpolate the resulting image with bilinear interpolation (that I have
> discovered) is the ESRI ArcIMS ArcMap image service and the ESRI ArcGIS
> Server.
> 
> I kind of hoped that the new AGG rendering back-end would give an option
> to set the interpolation method used in the output, but I see no
> difference when using AGG instead of GD. (IMAGEMODE is 24bit (RGB) PNG in
> both cases). Am I missing something here, or do not AGG increase the image
> quality if the resulting image if the data source is only rasters? Does
> anyone have any experience concerning this issue, and maybe could give me
> some advice?
> 
> ArcGIS Server
>  http://www.nabble.com/file/p12754990/ArcGIS_Server.png 
> 
> 
> Mapserver 5.0 rc2 with AGG rendering
>  http://www.nabble.com/file/p12754990/MapServer_5rc2_AGG.png 
> 
> Regards,
> Pål Kristensen
> Norwegian Mapping and Cadastre Authority
> 

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