.\" -*- mode: troff; coding: utf-8 -*-
.\" Automatically generated by Pod::Man v6.0.2 (Pod::Simple 3.45)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>.
.ie n \{\
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Required to disable full justification in groff 1.23.0.
.if n .ds AD l
.\" ========================================================================
.\"
.IX Title "TRANSVERSEMERCATORPROJ 1"
.TH TRANSVERSEMERCATORPROJ 1 2025-09-30 "GeographicLib 2.6" "GeographicLib Utilities"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
TransverseMercatorProj \-\- perform transverse Mercator projection
.SH SYNOPSIS
.IX Header "SYNOPSIS"
\&\fBTransverseMercatorProj\fR [ \fB\-s\fR | \fB\-t\fR ]
[ \fB\-l\fR \fIlon0\fR ] [ \fB\-k\fR \fIk0\fR ] [ \fB\-r\fR ]
[ \fB\-e\fR \fIa\fR \fIf\fR ] [ \fB\-w\fR ] [ \fB\-p\fR \fIprec\fR ]
[ \fB\-\-comment\-delimiter\fR \fIcommentdelim\fR ]
[ \fB\-\-version\fR | \fB\-h\fR | \fB\-\-help\fR ]
[ \fB\-\-input\-file\fR \fIinfile\fR | \fB\-\-input\-string\fR \fIinstring\fR ]
[ \fB\-\-line\-separator\fR \fIlinesep\fR ]
[ \fB\-\-output\-file\fR \fIoutfile\fR ]
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Perform the transverse Mercator projections.  Convert geodetic
coordinates to transverse Mercator coordinates.  The central meridian is
given by \fIlon0\fR.  The longitude of origin is the equator.  The scale on
the central meridian is \fIk0\fR.  By default an implementation of the
exact transverse Mercator projection is used.
.PP
Geodetic coordinates are provided on standard input as a set of lines
containing (blank separated) \fIlatitude\fR and \fIlongitude\fR (decimal
degrees or degrees, minutes, seconds); for detils on the allowed
formats for latitude and longitude, see the \f(CW\*(C`GEOGRAPHIC COORDINATES\*(C'\fR
section of \fBGeoConvert\fR\|(1).  For each set of geodetic coordinates, the
corresponding projected easting, \fIx\fR, and northing, \fIy\fR, (meters) are
printed on standard output together with the meridian convergence
\&\fIgamma\fR (degrees) and scale \fIk\fR.  The meridian convergence is the
bearing of grid north (the \fIy\fR axis) measured clockwise from true north.
.SH OPTIONS
.IX Header "OPTIONS"
.IP \fB\-s\fR 4
.IX Item "-s"
use the sixth\-order Krueger series approximation to the transverse
Mercator projection instead of the exact projection.
.IP \fB\-t\fR 4
.IX Item "-t"
use the exact algorithm with the "EXTENDED DOMAIN".
.IP "\fB\-l\fR \fIlon0\fR" 4
.IX Item "-l lon0"
specify the longitude of origin \fIlon0\fR (degrees, default 0).
.IP "\fB\-k\fR \fIk0\fR" 4
.IX Item "-k k0"
specify the scale \fIk0\fR on the central meridian (default 0.9996).
.IP \fB\-r\fR 4
.IX Item "-r"
perform the reverse projection.  \fIx\fR and \fIy\fR are given on standard
input and each line of standard output gives \fIlatitude\fR, \fIlongitude\fR,
\&\fIgamma\fR, and \fIk\fR.
.IP "\fB\-e\fR \fIa\fR \fIf\fR" 4
.IX Item "-e a f"
specify the ellipsoid via the equatorial radius, \fIa\fR and
the flattening, \fIf\fR.  Setting \fIf\fR = 0 results in a sphere.  Specify
\&\fIf\fR < 0 for a prolate ellipsoid.  A simple fraction, e.g., 1/297,
is allowed for \fIf\fR.  By default, the WGS84 ellipsoid is used, \fIa\fR =
6378137 m, \fIf\fR = 1/298.257223563.  If the exact algorithm is used, \fIf\fR
must be positive.
.IP \fB\-w\fR 4
.IX Item "-w"
on input and output, longitude precedes latitude (except that on input
this can be overridden by a hemisphere designator, \fIN\fR, \fIS\fR, \fIE\fR,
\&\fIW\fR).
.IP "\fB\-p\fR \fIprec\fR" 4
.IX Item "-p prec"
set the output precision to \fIprec\fR (default 6).  \fIprec\fR is the number
of digits after the decimal point for lengths (in meters).  For
latitudes and longitudes (in degrees), the number of digits after the
decimal point is \fIprec\fR + 5.  For the convergence (in degrees) and
scale, the number of digits after the decimal point is \fIprec\fR + 6.
.IP "\fB\-\-comment\-delimiter\fR \fIcommentdelim\fR" 4
.IX Item "--comment-delimiter commentdelim"
set the comment delimiter to \fIcommentdelim\fR (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).
.IP \fB\-\-version\fR 4
.IX Item "--version"
print version and exit.
.IP \fB\-h\fR 4
.IX Item "-h"
print usage and exit.
.IP \fB\-\-help\fR 4
.IX Item "--help"
print full documentation and exit.
.IP "\fB\-\-input\-file\fR \fIinfile\fR" 4
.IX Item "--input-file infile"
read input from the file \fIinfile\fR instead of from standard input; a file
name of "\-" stands for standard input.
.IP "\fB\-\-input\-string\fR \fIinstring\fR" 4
.IX Item "--input-string instring"
read input from the string \fIinstring\fR instead of from standard input.
All occurrences of the line separator character (default is a semicolon)
in \fIinstring\fR are converted to newlines before the reading begins.
.IP "\fB\-\-line\-separator\fR \fIlinesep\fR" 4
.IX Item "--line-separator linesep"
set the line separator character to \fIlinesep\fR.  By default this is a
semicolon.
.IP "\fB\-\-output\-file\fR \fIoutfile\fR" 4
.IX Item "--output-file outfile"
write output to the file \fIoutfile\fR instead of to standard output; a
file name of "\-" stands for standard output.
.SH "EXTENDED DOMAIN"
.IX Header "EXTENDED DOMAIN"
The exact transverse Mercator projection has a \fIbranch point\fR on the
equator at longitudes (relative to \fIlon0\fR) of +/\- (1 \- \fIe\fR) 90 =
82.636..., where \fIe\fR is the eccentricity of the ellipsoid.  The
standard convention for handling this branch point is to map positive
(negative) latitudes into positive (negative) northings \fIy\fR; i.e., a
branch cut is placed on the equator.  With the \fIextended\fR domain, the
northern sheet of the projection is extended into the south hemisphere
by pushing the branch cut south from the branch points.  See the
reference below for details.
.SH EXAMPLES
.IX Header "EXAMPLES"
.Vb 4
\&   echo 0 90 | TransverseMercatorProj
\&   => 25953592.84 9997964.94 90 18.40
\&   echo 260e5 100e5 | TransverseMercatorProj \-r
\&   => \-0.02 90.00 90.01 18.48
.Ve
.SH ERRORS
.IX Header "ERRORS"
An illegal line of input will print an error message to standard output
beginning with \f(CW\*(C`ERROR:\*(C'\fR and causes \fBTransverseMercatorProj\fR to return an exit
code of 1.  However, an error does not cause \fBTransverseMercatorProj\fR to
terminate; following lines will be converted.
.SH AUTHOR
.IX Header "AUTHOR"
\&\fBTransverseMercatorProj\fR was written by Charles Karney.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
The algorithms for the transverse Mercator projection are described in
C. F. F. Karney, \fITransverse Mercator with an accuracy of a few
nanometers\fR, J. Geodesy \fB85\fR(8), 475\-485 (Aug. 2011); DOI
<https://doi.org/10.1007/s00190\-011\-0445\-3>; preprint
<https://arxiv.org/abs/1002.1417>.  The explanation of the extended
domain of the projection with the \fB\-t\fR option is given in Section 5 of
this paper.
.SH HISTORY
.IX Header "HISTORY"
\&\fBTransverseMercatorProj\fR was added to GeographicLib,
<https://geographiclib.sourceforge.io>, in 2009\-01.
Prior to version 1.9 it was called TransverseMercatorTest (and its
interface was slightly different).