[mapserver-users] cutom EPSG db for Canada problem

[Daniel Morissette]

Actually, 42201 is not part of the EPSG file that we distribute with our
applications and that we made available for download at  
http://www2.dmsolutions.ca/mapserver/dl/proj4-epsg-with-42xxx.zip

Our file contains only special codes 42101, 42102, and 42304, so 42201
must have been added by someone else.

If this file with a broken EPSG:42201 definition really came from us
then can you please point us to it so that we can fix it?

Thanks,

Daniel


Frank Warmerdam wrote:
> 
> Chuanyun Fei wrote:
> > Hi All,
> >
> > We current add some epsg codes (got from DM Solutions) for Canada and
> > North American into the epsg db located in c:\proj\epsg and
> > C:\proj\nad\epsg, for example:
> >
> > # WGS84 / Ortho NorthAm
> > <42201> +proj=ortho +lat_0=45.0 +long_0=-100.0 +x_0=0.0 +y_0=0.0
> > +ellps=WGS84 +datum=WGS84 +units=m no_defs <>
> >
> > Our MapScript and MapServer are 3.6 runing on Win2000. We wondering why
> > some points work, some don't. For example:
> >
> > convert EPSG:4326 => EPSG:42201:
> > input (-128, 32)  => (4262324.1145246,4744679.5950324)
> > input (-128, 31)  => nothing
> >
> > Is there some restraints for the input points (bounding box)?
> >
> > Thanks a lot in advance.
> 
> Chuanyun Fei,
> 
> I believe the problem you are encountering is that the +long_0=-100 flag is
> being ignored because there is no such flag.  Use +lon_0=-100.  Without this
> change you are 100 degrees further away from the region of validity for this
> projection than you think causing a numeric problems.
> 
> This is also hinted at by the very large X values (nearly 5 million meters)
> you are getting.
> 
> It seems that the DM Solutions special coordinate systems need a fix.
> 
> Best regards,
> 
> --
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