[Mapserver-users] Polar stereographic projection misbehaviour

[Frank Warmerdam]

Sebastian Albrecht wrote:
> Hello Frank,
> 
> 
>>My suggestion would be
>>to reproject your lat/long data into polar stereographic ahead of time
>>to keep things well behaved in mapserver.
> 
> 
> That's what I did with the coastlines. The problem is the graticule
> (which is dynamically generated by Mapserver) and my ship tracks which
> should be dynamic, too.
> 
> But if there is no othe solution, I will have to think about a dynamic
> call of PROJ and generation of my ship tracks :\

Sebastian,

Well, we could also look at improving the logic of the search rectangle
reprojecting code.  There has been some work in this area (are you running
Mapserver-dev? or stock 4.0?).  There if we determined that things were
going to hell in a handbasket, we just return a worldwide area on the theory
that it is better to select too much data for drawing rather than too little.

We might be able to add an option in the mapfile to basically defeat the
search rectangle reprojection (always use the whole world for some layer), or
to recognise what has happened.

Best regards,

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent