[Proj] C API to calculate distances

Michael P Finn mfinn at usgs.gov
Mon Jan 22 12:22:37 EST 2007


Oliver,

Sounds like you want to use the Vincinty calculations for geodesic 
distance. Try one of these sites: 
http://www.movable-type.co.uk/scripts/LatLongVincenty.html or 
http://www.ga.gov.au/geodesy/datums/vincenty_inverse.jsp


Mike



Michael P. Finn
Research Cartographer
National Geospatial Technical Operations Center
U. S. Geological Survey
Rolla, MO

(573) 308-3931
mfinn at usgs.gov 

http://carto-research.er.usgs.gov/







Oliver Eichler <oliver.eichler at dspsolutions.de> 
Sent by: proj-bounces at lists.maptools.org
01/22/2007 05:14 AM
Please respond to
oliver.eichler at dspsolutions.de; Please respond to
"PROJ.4 and general Projections Discussions"    <proj at lists.maptools.org>


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Subject
[Proj] C API to calculate distances







Hi,

I wonder if there is a C API to calculate the real great circle distance
of two points on a WGS84 ellipsoid. I know there is "geod" on the
command line. I had a look at it's source code however this looked quite
complicated. As this must be a standard problem isn't there something 
like;

distance(p1,p1, d, dir)

p1:  point 1
p2:  point 2
d:   distance
dir: direction in degrees





Oliver
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