[gdal-dev] OGRGeometry Distance

Even Rouault even.rouault at mines-paris.org
Mon Sep 21 14:37:51 EDT 2009

Selon Christopher Barker <Chris.Barker at noaa.gov>:

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 :

(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
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> Chris.Barker at noaa.gov
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