166 lines
5.5 KiB
Plaintext
166 lines
5.5 KiB
Plaintext
=head1 NAME
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ConicProj -- perform conic projections
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=head1 SYNOPSIS
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B<ConicProj> ( B<-c> | B<-a> ) I<lat1> I<lat2>
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[ B<-l> I<lon0> ] [ B<-k> I<k1> ] [ B<-r> ]
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[ B<-e> I<a> I<f> ] [ B<-w> ] [ B<-p> I<prec> ]
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[ B<--comment-delimiter> I<commentdelim> ]
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[ B<--version> | B<-h> | B<--help> ]
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[ B<--input-file> I<infile> | B<--input-string> I<instring> ]
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[ B<--line-separator> I<linesep> ]
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[ B<--output-file> I<outfile> ]
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=head1 DESCRIPTION
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Perform one of two conic projections geodesics. Convert geodetic
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coordinates to either Lambert conformal conic or Albers equal area
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coordinates. The standard latitudes I<lat1> and I<lat2> are specified
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by that the B<-c> option (for Lambert conformal conic) or the B<-a>
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option (for Albers equal area). At least one of these options must be
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given (the last one given is used). Specify I<lat1> = I<lat2>, to
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obtain the case with a single standard parallel. The central meridian
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is given by I<lon0>. The longitude of origin is given by the latitude
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of minimum (azimuthal) scale for Lambert conformal conic (Albers equal
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area). The (azimuthal) scale on the standard parallels is I<k1>.
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Geodetic coordinates are provided on standard input as a set of lines
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containing (blank separated) I<latitude> and I<longitude> (decimal
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degrees or degrees, minutes, seconds); for details on the allowed
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formats for latitude and longitude, see the C<GEOGRAPHIC COORDINATES>
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section of GeoConvert(1). For each set of geodetic coordinates, the
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corresponding projected easting, I<x>, and northing, I<y>, (meters) are
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printed on standard output together with the meridian convergence
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I<gamma> (degrees) and (azimuthal) scale I<k>. For Albers equal area,
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the radial scale is 1/I<k>. The meridian convergence is the bearing of
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the I<y> axis measured clockwise from true north.
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Special cases of the Lambert conformal projection are the Mercator
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projection (the standard latitudes equal and opposite) and the polar
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stereographic projection (both standard latitudes correspond to the same
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pole). Special cases of the Albers equal area projection are the
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cylindrical equal area projection (the standard latitudes equal and
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opposite), the Lambert azimuthal equal area projection (both standard
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latitude corresponds to the same pole), and the Lambert equal area conic
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projection (one standard parallel is at a pole).
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=head1 OPTIONS
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=over
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=item B<-c> I<lat1> I<lat2>
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use the Lambert conformal conic projection with standard parallels
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I<lat1> and I<lat2>.
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=item B<-a> I<lat1> I<lat2>
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use the Albers equal area projection with standard parallels I<lat1> and
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I<lat2>.
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=item B<-l> I<lon0>
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specify the longitude of origin I<lon0> (degrees, default 0).
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=item B<-k> I<k1>
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specify the (azimuthal) scale I<k1> on the standard parallels (default
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1).
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=item B<-r>
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perform the reverse projection. I<x> and I<y> are given on standard
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input and each line of standard output gives I<latitude>, I<longitude>,
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I<gamma>, and I<k>.
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=item B<-e> I<a> I<f>
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specify the ellipsoid via the equatorial radius, I<a> and
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the flattening, I<f>. Setting I<f> = 0 results in a sphere. Specify
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I<f> E<lt> 0 for a prolate ellipsoid. A simple fraction, e.g., 1/297,
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is allowed for I<f>. By default, the WGS84 ellipsoid is used, I<a> =
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6378137 m, I<f> = 1/298.257223563.
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=item B<-w>
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toggle the longitude first flag (it starts off); if the flag is on, then
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on input and output, longitude precedes latitude (except that, on input,
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this can be overridden by a hemisphere designator, I<N>, I<S>, I<E>,
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I<W>).
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=item B<-p> I<prec>
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set the output precision to I<prec> (default 6). I<prec> is the number
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of digits after the decimal point for lengths (in meters). For
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latitudes and longitudes (in degrees), the number of digits after the
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decimal point is I<prec> + 5. For the convergence (in degrees) and
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scale, the number of digits after the decimal point is I<prec> + 6.
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=item B<--comment-delimiter> I<commentdelim>
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set the comment delimiter to I<commentdelim> (e.g., "#" or "//"). If
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set, the input lines will be scanned for this delimiter and, if found,
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the delimiter and the rest of the line will be removed prior to
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processing and subsequently appended to the output line (separated by a
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space).
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=item B<--version>
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print version and exit.
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=item B<-h>
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print usage and exit.
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=item B<--help>
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print full documentation and exit.
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=item B<--input-file> I<infile>
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read input from the file I<infile> instead of from standard input; a file
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name of "-" stands for standard input.
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=item B<--input-string> I<instring>
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read input from the string I<instring> instead of from standard input.
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All occurrences of the line separator character (default is a semicolon)
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in I<instring> are converted to newlines before the reading begins.
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=item B<--line-separator> I<linesep>
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set the line separator character to I<linesep>. By default this is a
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semicolon.
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=item B<--output-file> I<outfile>
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write output to the file I<outfile> instead of to standard output; a
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file name of "-" stands for standard output.
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=back
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=head1 EXAMPLES
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echo 39.95N 75.17W | ConicProj -c 40d58 39d56 -l 77d45W
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=> 220445 -52372 1.67 1.0
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echo 220445 -52372 | ConicProj -c 40d58 39d56 -l 77d45W -r
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=> 39.95 -75.17 1.67 1.0
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=head1 ERRORS
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An illegal line of input will print an error message to standard output
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beginning with C<ERROR:> and causes B<ConicProj> to return an exit
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code of 1. However, an error does not cause B<ConicProj> to
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terminate; following lines will be converted.
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=head1 AUTHOR
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B<ConicProj> was written by Charles Karney.
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=head1 HISTORY
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B<ConicProj> was added to GeographicLib,
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L<https://geographiclib.sourceforge.io>, in version 1.9.
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