[gdal-dev] OGRGeometry Distance

[Christopher Barker]

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



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Christopher Barker, Ph.D.
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