Hi Even; Thank you very much for your help.
Regards, Yilmaz On Mon, Sep 21, 2009 at 9:37 PM, Even Rouault <[email protected]> wrote: > Selon Christopher Barker <[email protected]>: > > I'd note that in the OGR XPlane driver, a function is available to compute the > distance on the spheroid. You could use it if you don't need much accuracy : > http://trac.osgeo.org/gdal/browser/trunk/gdal/ogr/ogrsf_frmts/xplane/ogr_xplane_geo_utils.cpp > > (It's an internal function to OGR, so you'd have to copy&paste it in your > code, > or add a CPL_DLL decoration in the corresponding .h and rebuild GDAL) > >> Yilmaz Arslanoglu wrote: >> > I wanted to compute the distance between two points, >> >> you need to be clear by what you mean here: I suspect you mean: >> >> "The shortest distance between two points following the surface of the >> earth" >> >> In which case, what you are looking for is referred to as the geodesic >> distance: >> >> http://www.vterrain.org/Misc/distance.html >> >> To do this accurately (and you may not need much accuracy!) on an >> ellipsoid requires a fair bit of math. I don't know if it's built in to >> OGR or PROJ at this point, but there are a few libraries out that that >> do it, including Gerald I. Evenden's "geodesic" lib, which can be found >> here: >> >> http://home.comcast.net/~gevenden56/geodesy/project/ >> >> -Chris >> >> >> >> -- >> Christopher Barker, Ph.D. >> Oceanographer >> >> Emergency Response Division >> NOAA/NOS/OR&R (206) 526-6959 voice >> 7600 Sand Point Way NE (206) 526-6329 fax >> Seattle, WA 98115 (206) 526-6317 main reception >> >> [email protected] >> _______________________________________________ >> gdal-dev mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
