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GEOCONVERT(1) GeographicLib Utilities GEOCONVERT(1)
NAME
GeoConvert -- convert geographic coordinates
SYNOPSIS
GeoConvert [ -g | -d | -: | -u | -m | -c ] [ -z zone | -s | -t ] [ -n ]
[ -w ] [ -p prec ] [ -l | -a ] [ --comment-delimiter commentdelim ] [
--version | -h | --help ] [ --input-file infile | --input-string
instring ] [ --line-separator linesep ] [ --output-file outfile ]
DESCRIPTION
GeoConvert reads from standard input interpreting each line as a
geographic coordinate and prints the coordinate in the format specified
by the options on standard output. The input is interpreted in one of
three different ways depending on how many space or comma delimited
tokens there are on the line. The options -g, -d, -u, and -m govern
the format of output. In all cases, the WGS84 model of the earth is
used (a = 6378137 m, f = 1/298.257223563).
geographic
2 tokens (output options -g, -d, or -:) given as latitude longitude
using decimal degrees or degrees, minutes, and seconds. Latitude
is given first (unless the -w option is given). See "GEOGRAPHIC
COORDINATES" for a description of the format. For example, the
following are all equivalent
33.3 44.4
E44.4 N33.3
33d18'N 44d24'E
44d24 33d18N
33:18 +44:24
UTM/UPS
3 tokens (output option -u) given as zone+hemisphere easting
northing or easting northing zone+hemisphere, where hemisphere is
either n (or north) or s (or south). The zone is absent for a UPS
specification. For example,
38n 444140.54 3684706.36
444140.54 3684706.36 38n
s 2173854.98 2985980.58
2173854.98 2985980.58 s
MRGS
1 token (output option -m) is used to specify the center of an MGRS
grid square. For example,
38SMB4484
38SMB44140847064
OPTIONS
-g output latitude and longitude using decimal degrees. Default
output mode.
-d output latitude and longitude using degrees, minutes, and seconds
(DMS).
-: like -d, except use : as a separator instead of the d, ', and "
delimiters.
-u output UTM or UPS.
-m output MGRS.
-c output meridian convergence and scale for the corresponding UTM or
UPS projection. Convergence is the bearing of grid north given as
degrees clockwise from true north.
-z set the zone to zone for output. Use either 0 < zone <= 60 for a
UTM zone or zone = 0 for UPS. Alternatively use a zone+hemisphere
designation, e.g., 38n. See "ZONE".
-s use the standard UPS and UTM zones.
-t similar to -s but forces UPS regions to the closest UTM zone.
-n on input, MGRS coordinates refer to the south-west corner of the
MGRS square instead of the center; see "MGRS".
-w on input and output, longitude precedes latitude (except that, on
input, this can be overridden by a hemisphere designator, N, S, E,
W).
-p set the output precision to prec (default 0); prec is the precision
relative to 1 m. See "PRECISION".
-l on output, UTM/UPS uses the long forms north and south to designate
the hemisphere instead of n or s.
-a on output, UTM/UPS uses the abbreviations n and s to designate the
hemisphere instead of north or south; this is the default
representation.
--comment-delimiter
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
read input from the file infile instead of from standard input; a
file name of "-" stands for standard input.
--input-string
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
set the line separator character to linesep. By default this is a
semicolon.
--output-file
write output to the file outfile instead of to standard output; a
file name of "-" stands for standard output.
PRECISION
prec gives precision of the output with prec = 0 giving 1 m precision,
prec = 3 giving 1 mm precision, etc. prec is the number of digits
after the decimal point for UTM/UPS. The number of digits per
coordinate for MGRS is 5 + prec. For decimal degrees, the number of
digits after the decimal point is 5 + prec. For DMS (degree, minute,
seconds) output, the number of digits after the decimal point in the
seconds components is 1 + prec; if this is negative then use minutes
(prec = -2 or -3) or degrees (prec <= -4) as the least significant
component. Print convergence, resp. scale, with 5 + prec, resp. 7 +
prec, digits after the decimal point. The minimum value of prec is -5
and the maximum is 9 for UTM/UPS, 9 for decimal degrees, 10 for DMS, 6
for MGRS, and 8 for convergence and scale.
GEOGRAPHIC COORDINATES
The utility accepts geographic coordinates, latitude and longitude, in
a number of common formats. Latitude precedes longitude, unless the -w
option is given which switches this convention. On input, either
coordinate may be given first by appending or prepending N or S to the
latitude and E or W to the longitude. These hemisphere designators
carry an implied sign, positive for N and E and negative for S and W.
This sign multiplies any +/- sign prefixing the coordinate. The
coordinates may be given as decimal degree or as degrees, minutes, and
seconds. d, ', and " are used to denote degrees, minutes, and seconds,
with the least significant designator optional. (See "QUOTING" for how
to quote the characters ' and " when entering coordinates on the
command line.) Alternatively, : (colon) may be used to separate the
various components. Only the final component of coordinate can include
a decimal point, and the minutes and seconds components must be less
than 60.
It is also possible to carry out addition or subtraction operations in
geographic coordinates. If the coordinate includes interior signs
(i.e., not at the beginning or immediately after an initial hemisphere
designator), then the coordinate is split before such signs; the pieces
are parsed separately and the results summed. For example the point
15" east of 39N 70W is
39N 70W+0:0:15E
WARNING: "Exponential" notation is not recognized for geographic
coordinates; instead 7.0E+1 is parsed as (7.0E) + (+1), yielding the
same result as 8.0E.
Various unicode characters (encoded with UTF-8) may also be used to
denote degrees, minutes, and seconds, e.g., the degree, prime, and
double prime symbols; in addition two single quotes can be used to
represent ".
The other GeographicLib utilities use the same rules for interpreting
geographic coordinates; in addition, azimuths and arc lengths are
interpreted the same way.
QUOTING
Unfortunately the characters ' and " have special meanings in many
shells and have to be entered with care. However note (1) that the
trailing designator is optional and that (2) you can use colons as a
separator character. Thus 10d20' can be entered as 10d20 or 10:20 and
10d20'30" can be entered as 10:20:30.
Unix shells (sh, bash, tsch)
The characters ' and " can be quoted by preceding them with a \
(backslash); or you can quote a string containing ' with a pair of
"s. The two alternatives are illustrated by
echo 10d20\'30\" "20d30'40" | GeoConvert -d -p -1
=> 10d20'30"N 020d30'40"E
Quoting of command line arguments is similar
GeoConvert -d -p -1 --input-string "10d20'30\" 20d30'40"
=> 10d20'30"N 020d30'40"E
Windows command shell (cmd)
The ' character needs no quoting; the " character can either be
quoted by a ^ or can be represented by typing ' twice. (This
quoting is usually unnecessary because the trailing designator can
be omitted.) Thus
echo 10d20'30'' 20d30'40 | GeoConvert -d -p -1
=> 10d20'30"N 020d30'40"E
Use \ to quote the " character in a command line argument
GeoConvert -d -p -1 --input-string "10d20'30\" 20d30'40"
=> 10d20'30"N 020d30'40"E
Input from a file
No quoting need be done if the input from a file. Thus each line
of the file "input.txt" should just contain the plain coordinates.
GeoConvert -d -p -1 < input.txt
MGRS
MGRS coordinates represent a square patch of the earth, thus
"38SMB4488" is in zone "38n" with 444km <= easting < 445km and 3688km
<= northing < 3689km. Consistent with this representation, coordinates
are truncated (instead of rounded) to the requested precision.
Similarly, on input an MGRS coordinate represents the center of the
square ("38n 444500 3688500" in the example above). However, if the -n
option is given then the south-west corner of the square is returned
instead ("38n 444000 3688000" in the example above).
ZONE
If the input is geographic, GeoConvert uses the standard rules of
selecting UTM vs UPS and for assigning the UTM zone (with the Norway
and Svalbard exceptions). If the input is UTM/UPS or MGRS, then the
choice between UTM and UPS and the UTM zone mirrors the input. The -z
zone, -s, and -t options allow these rules to be overridden with zone =
0 being used to indicate UPS. For example, the point
79.9S 6.1E
corresponds to possible MGRS coordinates
32CMS4324728161 (standard UTM zone = 32)
31CEM6066227959 (neighboring UTM zone = 31)
BBZ1945517770 (neighboring UPS zone)
then
echo 79.9S 6.1E | GeoConvert -p -3 -m => 32CMS4328
echo 31CEM6066227959 | GeoConvert -p -3 -m => 31CEM6027
echo 31CEM6066227959 | GeoConvert -p -3 -m -s => 32CMS4328
echo 31CEM6066227959 | GeoConvert -p -3 -m -z 0 => BBZ1917
Is zone is specified with a hemisphere, then this is honored when
printing UTM coordinates:
echo -1 3 | GeoConvert -u => 31s 500000 9889470
echo -1 3 | GeoConvert -u -z 31 => 31s 500000 9889470
echo -1 3 | GeoConvert -u -z 31s => 31s 500000 9889470
echo -1 3 | GeoConvert -u -z 31n => 31n 500000 -110530
NOTE: the letter in the zone specification for UTM is a hemisphere
designator n or s and not an MGRS latitude band letter. Convert the
MGRS latitude band letter to a hemisphere as follows: replace C thru M
by s (or south); replace N thru X by n (or north).
EXAMPLES
echo 38SMB4488 | GeoConvert => 33.33424 44.40363
echo 38SMB4488 | GeoConvert -: -p 1 => 33:20:03.25N 044:2413.06E
echo 38SMB4488 | GeoConvert -u => 38n 444500 3688500
echo E44d24 N33d20 | GeoConvert -m -p -3 => 38SMB4488
GeoConvert can be used to do simple arithmetic using degree, minutes,
and seconds. For example, sometimes data is tiled in 15 second squares
tagged by the DMS representation of the SW corner. The tags of the
tile at 38:59:45N 077:02:00W and its 8 neighbors are then given by
t=0:0:15
for y in -$t +0 +$t; do
for x in -$t +0 +$t; do
echo 38:59:45N$y 077:02:00W$x
done
done | GeoConvert -: -p -1 | tr -d ': '
=>
385930N0770215W
385930N0770200W
385930N0770145W
385945N0770215W
385945N0770200W
385945N0770145W
390000N0770215W
390000N0770200W
390000N0770145W
ERRORS
An illegal line of input will print an error message to standard output
beginning with "ERROR:" and causes GeoConvert to return an exit code of
1. However, an error does not cause GeoConvert to terminate; following
lines will be converted.
ABBREVIATIONS
UTM Universal Transverse Mercator,
<https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system>.
UPS Universal Polar Stereographic,
<https://en.wikipedia.org/wiki/Universal_Polar_Stereographic>.
MGRS
Military Grid Reference System,
<https://en.wikipedia.org/wiki/Military_grid_reference_system>.
WGS84
World Geodetic System 1984, <https://en.wikipedia.org/wiki/WGS84>.
SEE ALSO
An online version of this utility is availbable at
<http://geographiclib.sourceforge.net/cgi-bin/GeoConvert>.
The algorithms for the transverse Mercator projection are described in
C. F. F. Karney, Transverse Mercator with an accuracy of a few
nanometers, J. Geodesy 85(8), 475-485 (Aug. 2011); DOI
<https://dx.doi.org/10.1007/s00190-011-0445-3>; preprint
<http://arxiv.org/abs/1002.1417>.
AUTHOR
GeoConvert was written by Charles Karney.
HISTORY
GeoConvert was added to GeographicLib, <http://geographiclib.sf.net>,
in 2009-01.
GeographicLib 1.45 2015-09-30 GEOCONVERT(1)