NAME¶
GeoConvert -- convert geographic coordinates
SYNOPSIS¶
GeoConvert [
-g |
-d |
-: |
-u |
-m |
-c ] [
-p prec ] [
-z zone |
-s |
-t ] [
-n ] [
-w ] [
-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
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.) 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. Alternatively,
: (colon) may be used to separate the various components. Latitude is
given first (unless the -w option is given); however, on input,
either may be given first by appending or prepending N or S
to the latitude and E or W to the longitude. 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.
- -p
- set the output precision to prec (default 0); prec is the
precision relative to 1 m. See "PRECISION".
- -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).
- -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.
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).
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 ' 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 and the " character can be quoted by
a ^. (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
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
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,
<http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system>.
- UPS
- Universal Polar Stereographic,
<http://en.wikipedia.org/wiki/Universal_Polar_Stereographic>.
- MGRS
- Military Grid Reference System,
<http://en.wikipedia.org/wiki/Military_grid_reference_system>.
- WGS84
- World Geodetic System 1984,
<http://en.wikipedia.org/wiki/WGS84>.
SEE ALSO¶
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
<
http://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.