msProcessProjection(): Projection library error. no system list, errno: 13

[Adrian Popa]

Some javascript/style in this post has been disabled (why?)

Hello everyone!

I'm trying to troubleshoot a proj error, and I need your help! I have started this thread also on the mapserver mailing list, but I didn't find a solution yet: http://n2.nabble.com/msProcessProjection-Projection-library-error-no-system-list-errno-13-td3807641.html

I'm running mapserver, and I'm trying to configure it to act as a WMS server. My data is in wgs84 (epsg:4326) and I want to project it to mercator projection (epsg:900913).

I have configured the mapfile and the projections according to the Mapserver documentation and they work as long as the projection sections are defined like:
PROJECTION
    #spherical mercator/google
     "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs"
END

and

PROJECTION
    #WGS84
    "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
END

If I ask for EPSG projections (through WMS), I get the error in the subject.
Here is my WMS url:

http://terra/cgi-bin/mapserv?map=/var/www/html/map/rtc_base.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&LAYERS=GranitaJudete&STYLES=&SRS=EPSG:900913

I have tried to debug the problem by using shp2img, and it seems that mapserver tries to open /usr/share/proj/null as a file. I created a symlink between /usr/share/proj/epsg and /usr/share/proj/null, and now shp2img reads the file, but I get the same error while trying to call the WMS server.

My question is: how can I try to troubleshoot this issue - to see if there's a problem with proj?

I'd like to mention that I have added <900913> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m [hidden email] +no_defs to my epsg file and my proj version is:
[adrianp@terra mapserver]$ rpm -qa | grep proj
proj-devel-4.5.0-1.fc5
proj-4.5.0-1.fc5

Regards,
Adrian

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[Jean-Claude Repetto]

Hello,

Adrian Popa wrote :
>
> I'd like to mention that I have added <900913> +proj=merc +a=6378137
> +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m
> +nadgrids=@null +no_defs

The correct EPSG number for this projection is 3857 (900913 is obsolete).
Recent version of PROJ.4 contain this definition in the epsg file :

<3857> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0
+y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs <>

Regards,
Jean-Claude

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[Adrian Popa]

Some javascript/style in this post has been disabled (why?)

Hello Jean-Claude,

Unfortunately I can't upgrade my proj version because it's running on a kind of "legacy" server and changing it would break other things.
I have added the new projection code to the epsg file, but it still doesn't work. It gives the same error.

I would like an example of command line syntax for running proj - because I suspect it doesn't read the correct epsg file.

I don't know if it's important but my epsg file is a symlink to the real file. It may be an issue if the mapserver process running as apache can't read through symlinks...

[root@terra map]# ls -l /usr/share/proj/epsg
lrwxrwxrwx 1 root root 24 Oct 13 16:01 /usr/share/proj/epsg -> /usr/share/proj/nad/epsg

UPDATE:

Woohoo - I've changed the symlink to a hard link and now it works!
So, it seems there were some issues with apache, not being able to read through symlinks (maybe because it is disabled by default?)!
The moral of the story? Make sure /usr/share/proj/epsg is not a symlink!


Jean-Claude REPETTO wrote:

Hello,

Adrian Popa wrote :
  

I'd like to mention that I have added <900913> +proj=merc +a=6378137 
+b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m 
+nadgrids=@null +no_defs 
    

The correct EPSG number for this projection is 3857 (900913 is obsolete).
Recent version of PROJ.4 contain this definition in the epsg file :

<3857> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 
+y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs <>

Regards,
Jean-Claude

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