[Proj] NAD27 and WGS84 woes

[support.mn at elisanet.fi]

Yes,

this rises again the question about that there should be more
warnings when something has been omitted! The end user
might belive that the entries given have been handled, where
they actually are not.

The application can not do that, since these files are handled
deep in the proj4 library and the upper level does not know when
such situation happened.

Please write like:

if (!open_file(file_name))
{
___ call_warning_handler("Could not open file %s", file_name);
___ use_some_defaults();
}

And the warning handler can be a global procedure either
proj.4 defined (default does nothing) or the application defined,
where it delivers the message further to the end user the way
that is suitable for that specific application.

Regards: Janne.

---------------------------------

Michal Migurski <mike at stamen.com> kirjoitti: 
> On Nov 21, 2008, at 2:06 PM, Michal Migurski wrote:
> 
> > Frustrating, I don't know. I'm reading the FAQ's on datum shift  
> > files - FWIW, I'm using PROJ on a debian server where I've simply  
> > installed it all via Apt. I didn't build/install myself. Does the  
> > fact that my explicitly-given +towgs84 arguments have no effect mean  
> > anything here? Wouldn't those be replacements for missing grid shift  
> > files?
> 
> I should add that I have the following files on my system:
> 	/usr/share/proj/nad.lst
> 	/usr/share/proj/nad83
> 	/usr/share/proj/esri.extra
> 	/usr/share/proj/proj_def.dat
> 	/usr/share/proj/epsg /usr/share/proj/other.extra
> 	/usr/share/proj/esri /usr/share/proj/nad27
> 	/usr/share/proj/GL27
> 	/usr/share/proj/world
> 
> Would those be the conus files mentioned at http://trac.osgeo.org/proj/wiki/FAQ 
>   ? Nothing else in /usr seems to fit.
> 
> -mike.
> 
> ----------------------------------------------------------------
> michal migurski- mike at stamen.com
>                   415.558.1610
> 
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