[Proj] Any access to geodetic functions ??
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%
- 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)
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 :
>> 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)
> 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
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