NAME

       Conformal3Proj -- conformal projections for a triaxial ellipsoid

SYNOPSIS

       Conformal3Proj [ -r ] [ -t a b c | -e b e2 k2 kp2 ] [ -tx ax bx cx | -ex bx e2x k2x kp2x ] [ -d | -: ] [
       -w ] [ -p prec ] [ --comment-delimiter commentdelim ] [ --version | -h | --help ] [ --input-file infile |
       --input-string instring ] [ --line-separator linesep ] [ --output-file outfile ]

DESCRIPTION

       Project points using the Jacobi conformal projection.  By default, the coordinates of points on a
       triaxial ellipsoid are read from standard input as ellipsoidal latitude and longitude and the projected
       points are written to standard output as easting and northing.  The scale of the projection is appended
       to the output.  Specifying -r causes the reverse projection to be performed.

       If either -tx or -ex is given, then this describes a target ellipsoid onto which the points are
       conformally mapped via the Jacobi projections to intermediate spheres.  In this case, the meridian
       convergence and the scale are appended to the output.

OPTIONS

       -r  perform the reverse projection.

       -t a b c
           specify the ellipsoid via its major semiaxis a, median semiaxis b, and minor semixis c.  By default,
           we have a = 6378172 m, b = 6378102 m, c = 6356752 m, an approximate triaxial model of the earth.
           (With this model omg = 0deg, corresponds to lon = -14.93deg.

       -e b e2 k2 kp2
           specify the ellipsoid via the median semiaxis, b and the shape parameters e2 = (a^2 - c^2)/b^2, k2 =
           (b^2 - c^2)/(a^2 - c^2), and kp2 = (a^2 - b^2)/(a^2 - c^2).  Simple fractions are allowed for e2, k2,
           and kp2.  Internally, the supplied values of k2 and kp2 are normalized so that k2 + kp2 = 1.

       -tx ax bx cx
           specify the target ellipsoid via its semiaxes.

       -ex bx e2x k2x kp2x
           specify the target ellipsoid via its median semiaxes and shape parameters.

       -d  output angles as degrees, minutes, seconds instead of decimal degrees.

       -:  like -d, except use : as a separator instead of the d, ', and " delimiters.

       -w  toggle the longitude first flag (it starts off); if the flag is on, then on input and output,
           longitude precedes latitude (except that, on input, this can be overridden by a hemisphere
           designator, N, S, E, W).

       -p prec
           set the output precision to prec (default 3).  For distances, prec is the number of digits after the
           decimal point for ellipsoids which are approximately the same size as the Earth; for other ellipsoids
           the precision is adjusted to retain the same relative precision.  For latitudes and longitudes (in
           degrees), the number of digits after the decimal point is prec + 5.  For the scale, the precision is
           prec + 7.

       --comment-delimiter commentdelim
           set the comment delimiter to commentdelim (e.g., "#" or "//").  If set, the input lines will be
           scanned for this delimiter and, if found, the delimiter and the rest of the line will be removed
           prior to processing and subsequently appended to the output line (separated by a space).

       --version
           print version and exit.

       -h  print usage and exit.

       --help
           print full documentation and exit.

       --input-file infile
           read input from the file infile instead of from standard input; a file name of "-" stands for
           standard input.

       --input-string instring
           read input from the string instring instead of from standard input.  All occurrences of the line
           separator character (default is a semicolon) in instring are converted to newlines before the reading
           begins.

       --line-separator linesep
           set the line separator character to linesep.  By default this is a semicolon.

       --output-file outfile
           write output to the file outfile instead of to standard output; a file name of "-" stands for
           standard output.

EXAMPLES

          echo 33.3 44.4 | Conformal3Proj
          -5077732.396 3922571.859 1.1970343759
          echo -5077732.396 3922571.859 | Conformal3Proj -r
          33.30000000 44.40000000 1.1970343759

ERRORS

       An illegal line of input will print an error message to standard output beginning with "ERROR:" and
       causes Conformal3Proj to return an exit code of 1.  However, an error does not cause Conformal3Proj to
       terminate; following lines will be converted.

SEE ALSO

       Ellipsoidal coordinates are documented in Section 2 of C. F. F. Karney, Jacobi's solution for geodesics
       on a triaxial ellipsoid, Technical Report, SRI International, Nov. 2025,
       <https://arxiv.org/abs/2511.nnnnn>.

       The Wikipedia page, Geodesics on an ellipsoid, <https://en.wikipedia.org/wiki/Geodesics_on_an_ellipsoid>.

AUTHOR

       Conformal3Proj was written by Charles Karney.

HISTORY

       Conformal3Proj was added to GeographicLib, <https://geographiclib.sourceforge.io>, in version 2.6.

GeographicLib 2.7                                  2025-11-06                                  CONFORMAL3PROJ(1)