[mapserver-users] Version problems with overviews

[Jesse Cleary]

Hi folks

Just chatted with Frank W on IRC and he suggested that the issue is 
likely one with GDAL.  Turns out our GDAL version is "antique" so that 
will be a first place to upgrade.  Will try to reproduce the issue 
outside of MapServer to confirm...

Jesse




Jesse Cleary wrote:
> Hi folks
>
> Apologies for the re-post.  This went out initially prior to our 
> feedback loop last week and I thought it might have gotten lost in the 
> flood.  Or maybe I just can't take a hint...
>
> ---
>
> I'm dealing with a server with several versions of MapServer on it.  
> We are serving PNGs from the filesystem via CGI and working to speed 
> up performance.  I've been trying gdaladdo (-r nearest) to create 
> overviews for each image.  Mainly this works great and does give us 
> the speed increase I'm after.
>
> However, some of the MS versions on this box balk once I create an OVR 
> file on any given PNG.  Upon calling the PNG in question, I get a 500 
> "Internal Server error" error from Apache (2.0.46).  So the exact same 
> CGI call works without an OVR file and gives me the 500 error with an 
> OVR file present.  The Apache error logs don't contain a record of the 
> 500 error.  This is an issue because several existing web service hit 
> the problematic (and newer) version of MapServer and I don't want to 
> roll back to an older version which might have its own performance costs.
>
> I'm a bit baffled - anyone else seen this kind of error with overview 
> files?  I'd like some possibilities before I go back to the sys admin 
> of the machine in question.  Sorry I can't provide more details, but 
> it is not my box.  Thanks so much folks - apologies for the sketchy 
> details...
>
> Jesse
>
>
> This version of MapServer always works, *.OVR present or not:
> MapServer version 4.1 OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP SUPPORTS=PROJ 
> SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT 
> SUPPORTS=WFS_SERVER INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL 
> INPUT=SHAPEFILE
>
>
> This version of MapServer only works with no *.OVR file present:
> MapServer version 4.4.0 OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=PDF 
> SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER 
> SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT 
> INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE
>

-- 
Jesse A. Cleary
Department of Marine Sciences
UNC Chapel Hill

334 Chapman Hall
(919) 962-4987
jcleary at email.unc.edu