[Proj] Geod: I need a little guide

Gerald Evenden gerald.evenden at verizon.net
Sun Apr 25 14:52:43 EDT 2004

As I have been informed that *geod* is the geodesic program I will make
some comments:

1) there is a geod.1 file giving a brief explanation of usage.

2) ellipsoid parameters are selected in the same manner as for program
     *proj*.  For example, +ellps=besset, or +a=, +es=, +rf=, +R=, etc.

3) "forward" of "direct" input consists of lon, lat, azimuth and 
distance and
     the result is the lon-lat of the point and back azimuth.

4) Inverse input consists of lon_1, lat_1, lon_2, lat_2 and the distance
    between the points is returned as well as the azimuth from point 1 
    back azimuth from point 2.  Execute geod as "invgeod" or "geod -I 

5) There are a couple of other options.

If you could be more detailed in your needs I could perhaps suggest
an appropriate usage script.

Note: the name "geod" is short for geodesic which is synonymous with
"great circle" or shortest distance between two points on the sphere or
ellipsoid.  The request seems related to the geoid---a completely 

On Apr 25, 2004, at 6:56 AM, Paul Selormey wrote:

> Hello All,
> I need a little guide on the geod program, even the command options.
> In particular, any guide on the implementations? Is it based the
> WGS84 EGM96 model?
> Anyone knows the EGM96 binary file format in Geotrans?
> (the "egm96.grd" file) - I managed some format after reading
> the Geoid conversion sources, but do not know if it is the 
> complete/true
> picture.
> Best regards,
> Paul.
Jerry and the low riders: Daisy Mae and Joshua

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