[Proj] Any access to geodetic functions ??

Benoît Andrieu bea at ixsea.com
Wed Nov 12 04:06:55 EST 2008

Thank you so much for your answer, Frank.

So, this leads to some questions (that are somehow related...) :
- how are computed distance calculation between two points by softwares like 
Postgis for example ?
- is the best way to compute distance calculation to use UTM systems ? I 
have to compute distances that could be very long (hundreds of kilometers), 
strong accuracy is not required but I don't want to have more than 1% 
accuracy error.
- in what way are those functions distinct from the proj4 ? Am I wrong to 
use them ? Are there others functions in proj4 that would allow me to do the 
same things that I can do with those functions (distance calculation between 
two points and point positionning given initial point, distance and azimuth) 

Thanks again.

Best regards,

Benoît Andrieu
bea at ixsea.com
benoit.andrieu at gmail.com

----- Original Message ----- 
From: "Frank Warmerdam" <warmerdam at pobox.com>
To: "PROJ.4 and general Projections Discussions" <proj at lists.maptools.org>
Sent: Monday, November 10, 2008 10:59 PM
Subject: Re: [Proj] Any access to geodetic functions ??

> Benoît Andrieu wrote:
>> Hi all,
>>  We are using Proj4 in our softwares and we are using too Mapserver 
>> (FWTools compilation).
>> Actually, we are using custom built dlls for Proj4 : proj.dll and 
>> geod.dll. Those builds are based on the Proj4 4.5.0 version.
>> Why we have custom builds is that there was at the time no access to 
>> geodetic functions (and I need them... ^^).
>>  From what I remember, this is the kind of messages that made me make 
>> custom builds :
>> http://osdir.com/ml/gis.proj-4.devel/2006-12/msg00006.html
>>  We are actually switching from FWTools 1.3.2 to FWTools 2.2.6 which 
>> should embed Proj4 4.6.1.
>> So if I want my softwares to be synchronized with this version I would 
>> have to recompile a Proj4 4.6.1 to have access to the geodetic functions 
>> 'except' if they are already exported.
>>  So my question is : are the geodetic functions now exported ? (please 
>> answer yes ...)
>> And if affirmative, in which dlls will I be able to find them ? (coz I 
>> can't find them actually)
> Benoît,
> Currently the geodesic functions are not exported from proj.dll, nor
> (I think) are they even built into the DLL.   I'm a bit hesitant to treat
> them as part of the support PROJ.4 API since they are quite distinct
> from the core of PROJ.4.  The geod_* functions also depend on global
> variables which is not a pattern I'm keen on setting in stone.
> Best regards,
> -- 
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, 
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
> _______________________________________________
> Proj mailing list
> Proj at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/proj 

More information about the Proj mailing list