ConicProj -- perform conic projections
ConicProj (
-c |
-a )
lat1 lat2 [
-l
lon0 ] [
-k k1 ] [
-r ] [
-e a
f ] [
-w ] [
-p prec ] [
--comment-delimiter commentdelim ] [
--version |
-h |
--help ] [
--input-file infile |
--input-string instring ] [
--line-separator
linesep ] [
--output-file outfile ]
Perform one of two conic projections geodesics. Convert geodetic coordinates to
either Lambert conformal conic or Albers equal area coordinates. The standard
latitudes
lat1 and
lat2 are specified by that the
-c
option (for Lambert conformal conic) or the
-a option (for Albers equal
area). At least one of these options must be given (the last one given is
used). Specify
lat1 =
lat2, to obtain the case with a single
standard parallel. The central meridian is given by
lon0. The longitude
of origin is given by the latitude of minimum (azimuthal) scale for Lambert
conformal conic (Albers equal area). The (azimuthal) scale on the standard
parallels is
k1.
Geodetic coordinates are provided on standard input as a set of lines containing
(blank separated)
latitude and
longitude (decimal degrees or
degrees, minutes, seconds); for details on the allowed formats for latitude
and longitude, see the "GEOGRAPHIC COORDINATES" section of
GeoConvert(1). For each set of geodetic coordinates, the corresponding
projected easting,
x, and northing,
y, (meters) are printed on
standard output together with the meridian convergence
gamma (degrees)
and (azimuthal) scale
k. For Albers equal area, the radial scale is 1/
k. The meridian convergence is the bearing of the
y axis
measured clockwise from true north.
Special cases of the Lambert conformal projection are the Mercator projection
(the standard latitudes equal and opposite) and the polar stereographic
projection (both standard latitudes correspond to the same pole). Special
cases of the Albers equal area projection are the cylindrical equal area
projection (the standard latitudes equal and opposite), the Lambert azimuthal
equal area projection (both standard latitude corresponds to the same pole),
and the Lambert equal area conic projection (one standard parallel is at a
pole).
-
-c lat1 lat2
- use the Lambert conformal conic projection with standard
parallels lat1 and lat2.
-
-a lat1 lat2
- use the Albers equal area projection with standard
parallels lat1 and lat2.
-
-l lon0
- specify the longitude of origin lon0 (degrees,
default 0).
-
-k k1
- specify the (azimuthal) scale k1 on the standard
parallels (default 1).
- -r
- perform the reverse projection. x and y are
given on standard input and each line of standard output gives
latitude, longitude, gamma, and k.
-
-e a f
- specify the ellipsoid via the equatorial radius, a
and the flattening, f. Setting f = 0 results in a sphere.
Specify f < 0 for a prolate ellipsoid. A simple fraction, e.g.,
1/297, is allowed for f. By default, the WGS84 ellipsoid is used,
a = 6378137 m, f = 1/298.257223563.
- -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 6).
prec 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 prec + 5. For the convergence (in
degrees) and scale, the number of digits after the decimal point is
prec + 6.
-
--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.
echo 39.95N 75.17W | ConicProj -c 40d58 39d56 -l 77d45W
=> 220445 -52372 1.67 1.0
echo 220445 -52372 | ConicProj -c 40d58 39d56 -l 77d45W -r
=> 39.95 -75.17 1.67 1.0
An illegal line of input will print an error message to standard output
beginning with "ERROR:" and causes
ConicProj to return an
exit code of 1. However, an error does not cause
ConicProj to
terminate; following lines will be converted.
ConicProj was written by Charles Karney.
ConicProj was added to GeographicLib,
<
https://geographiclib.sourceforge.io>, in version 1.9.