Provided by: proj-bin_4.9.3-2_amd64 bug

NAME

       geod - direct geodesic computations
       invgeod - inverse geodesic computations

SYNOPSIS

       geod +ellps=<ellipse> [ -afFIlptwW [ args ] ] [ +args ] file[s]
       invgeod  +ellps=<ellipse>  [  -afFIlptwW  [  args ] ] [ +args ]
       file[s]

DESCRIPTION

       geod (direct) and invgeod (inverse)  perform  geodesic  ("Great
       Circle")  computations  for determining latitude, longitude and
       back  azimuth  of  a  terminus  point  given  a  initial  point
       latitude,  longitude,  azimuth  and  distance  (direct)  or the
       forward and back azimuths and distance between an  initial  and
       terminus point latitudes and longitudes (inverse).  The results
       are  accurate  to  round  off  for  |f|  <  1/50,  where  f  is
       flattening.   invgeod may not be available on all platforms; in
       this case call geod with the -I option.

       The following command-line options can appear in any order:

       -I     Specifies that the inverse geodesic computation is to be
              performed.   May  be  used  with execution of geod as an
              alternative to invgeod execution.

       -a     Latitude and longitudes  of  the  initial  and  terminal
              points,  forward  and  back  azimuths  and  distance are
              output.

       -ta    A specifies a character employed as the first  character
              to  denote  a  control line to be passed through without
              processing.

       -le    Gives a listing  of  all  the  ellipsoids  that  may  be
              selected with the +ellps= option.

       -lu    Gives  a  listing  of all the units that may be selected
              with the +units= option.

       -[f|F] format
              Format is a printf format string to control  the  output
              form of the geographic coordinate values (f) or distance
              value (F).  The  default  mode  is  DMS  for  geographic
              coordinates and "%.3f" for distance.

       -[w|W]n
              N  is  the  number  of  significant fractional digits to
              employ for  seconds  output  (when  the  option  is  not
              specified,  -w3  is  assumed).   When -W is employed the
              fields will be constant width with leading zeroes.

       -p     This option causes the azimuthal values to be output  as
              unsigned  DMS  numbers  between 0 and 360 degrees.  Also
              note -f.

       The +args command-line options  are  associated  with  geodetic
       parameters  for  specifying  the  ellipsoidal or sphere to use.
       See proj documentation for full list of  these  parameters  and
       controls.   The  options  are  processed in left to right order
       from the command line.  Reentry of an option  is  ignored  with
       the first occurrence assumed to be the desired value.

       One  or  more  files (processed in left to right order) specify
       the source of data to be transformed.  A  -  will  specify  the
       location  of  processing  standard  input.   If  no  files  are
       specified, the input is assumed to be from stdin.

       For direct determinations  input  data  must  be  in  latitude,
       longitude,  azimuth  and  distance  order  and  output  will be
       latitude, longitude and back azimuth  of  the  terminus  point.
       Latitude, longitude of the initial and terminus point are input
       for the inverse mode and respective forward  and  back  azimuth
       from  the initial and terminus points are output along with the
       distance between the points.

       Input  geographic  coordinates  (latitude  and  longitude)  and
       azimuthal  data  must  be  in decimal degrees or DMS format and
       input distance data  must  be  in  units  consistent  with  the
       ellipsoid major axis or sphere radius units.  The latitude must
       lie in the range  [-90d,90d].   Output  geographic  coordinates
       will  be  in  DMS  (if the -f switch is not employed) to 0.001"
       with  trailing,  zero-valued  minute-second   fields   deleted.
       Output distance data will be in the same units as the ellipsoid
       or sphere radius.

       The Earth's ellipsoidal figure may  be  selected  in  the  same
       manner as program proj by using +ellps=, +a=, +es=, etc.

       Geod  may  also  be used to determine intermediate points along
       either a geodesic line between two points or along  an  arc  of
       specified  distance  from a geographic point.  In both cases an
       initial point must be specified with +lat_1=lat and  +lon_1=lon
       parameters   and   either   a  terminus  point  +lat_2=lat  and
       +lon_2=lon or a distance and azimuth  from  the  initial  point
       with +S=distance and +A=azimuth must be specified.

       If  points  along  a  geodesic are to be determined then either
       +n_S=integer  specifying  the  number  of  intermediate  points
       and/or  +del_S=distance  specifying  the  incremental  distance
       between points must be specified.

       To determine points along an arc equidistant from  the  initial
       point  both  +del_A=angle  and  +n_A=integer  must be specified
       which determine the respective angular increments and number of
       points to be determined.

EXAMPLE

       The  following  script  determines  the  geodesic  azimuths and
       distance in U.S. statute miles from Boston,  MA,  to  Portland,
       OR:
             geod +ellps=clrk66 <<EOF -I +units=us-mi
             42d15'N 71d07'W 45d31'N 123d41'W
             EOF
       which gives the results:
             -66d31'50.141" 75d39'13.083" 2587.504
       where  the  first  two  values  are  the azimuth from Boston to
       Portland, the back azimuth from Portland to Boston followed  by
       the distance.

       An  example  of  forward  geodesic  use  is  to  use the Boston
       location and  determine  Portland's  location  by  azimuth  and
       distance:
             geod +ellps=clrk66 <<EOF +units=us-mi
             42d15'N 71d07'W -66d31'50.141" 2587.504
             EOF
       which gives:
             45d31'0.003"N 123d40'59.985"W 75d39'13.094"
       Note:  lack  of precision in the distance value compromises the
       precision of the Portland location.

SEE ALSO

       geodesic(3)

       GeographicLib, http://geographiclib.sf.net

       The GeodSolve utility in GeographicLib.  With  the  -E  option,
       this   solves  the  geodesic  problems  in  terms  of  elliptic
       integrals; the results are accurate for arbitrary f.

       C. F. F. Karney, Algorithms for Geodesics,
       J. Geodesy 87, 43-55 (2013);
       DOI: http://dx.doi.org/10.1007/s00190-012-0578-z
       http://geographiclib.sf.net/geod-addenda.html

       The online geodesic bibliography,
       http://geographiclib.sf.net/geodesic-papers/biblio.html

BUGS

       A     list     of     known     bugs     can      found      at
       https://github.com/OSGeo/proj.4/issues  where  new  bug reports
       can be submitted too.

HOME PAGE

       http://proj4.org/

                                      2016/02/16 Rel. 4.9.3                               GEOD(1)