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NAME

       m.cogo  - A simple utility for converting bearing and distance measurements to coordinates
       and vice versa.
       It assumes a cartesian coordinate system

KEYWORDS

       miscellaneous, distance, polar

SYNOPSIS

       m.cogo
       m.cogo --help
       m.cogo [-lrc]   [input=name]    [output=name]    [coordinates=east,north]    [--overwrite]
       [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -l
           Lines are labelled

       -r
           Convert from coordinates to bearing and distance

       -c
           Repeat the starting coordinate at the end to close a loop

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=name
           Name of input file
           Default: -

       output=name
           Name for output file
           Default: -

       coordinates=east,north
           Starting coordinate pair
           Default: 0.0,0.0

DESCRIPTION

       m.cogo converts data points between bearing and distance and X,Y coordinates.  Only simple
       bearing/distance or coordinate pairs  are  handled.  It  assumes  a  cartesian  coordinate
       system.

       Input  can be entered via standard input (default) or from the file input=name. Specifying
       the input as "-" also specifies standard input, and is useful for using the program  in  a
       pipeline.   Output  will  be  to  standard  output  unless  a  file name other than "-" is
       specified.  The input file must closely adhere to the following format, where up to  a  10
       character label is allowed but not required (see -l flag).

       Example COGO input:
          P23 N 23:14:12 W 340
          P24 S 04:18:56 E 230
          ...

       The  first  column  may contain a label and you must use the -l flag so the program knows.
       This is followed by a space, and then either the character ’N’ or ’S’ to indicate  whether
       the  bearing is relative to the north or south directions.  After another space, the angle
       begins in degrees, minutes, and seconds in "DDD:MM:SS.SSSS" format. Generally,  the  angle
       can  be  of the form digits + separator + digits + separator + digits [+ ’.’ + digits].  A
       space follows the angle, and is then followed by either the ’E’ or ’W’ characters. A space
       separates the bearing from the distance (which should be in appropriate linear units).

       Output of the above input:
          -134.140211 312.420236 P23
          -116.832837 83.072345 P24
          ...

       Unless specified with the coord option, calculations begin from (0,0).

NOTES

       For  those  unfamiliar with the notation for bearings: Picture yourself in the center of a
       circle.  The first hemispere notation tell you whether you should  face  north  or  south.
       Then  you  read the angle and either turn that many degrees to the east or west, depending
       on the second hemisphere notation.  Finally, you move <distance> units in  that  direction
       to get to the next station.

       m.cogo  can  be  run  either  non-interactively or interactively.  The program will be run
       non-interactively if the user specifies any parameter or flag. Use "m.cogo -", to run  the
       program in a pipeline.  Without any flags or parameters, m.cogo will prompt for each value
       using the familiar GRASS parser interface.

       This program is very simplistic, and will not handle  deviations  from  the  input  format
       explained  above.  Currently, the program doesn’t do anything particularly useful with the
       output.  However, it is envisioned that this program  will  be  extended  to  provide  the
       capability to generate vector and/or sites layers.

       Lines  may  be closed by using the -c flag or snapped with v.clean, lines may be converted
       to boundaries  with  v.type,  and  closed  boundaries  may  be  converted  to  areas  with
       v.centroids.

EXAMPLES

          m.cogo -l in=cogo.dat
       Where the cogo.dat input file looks like:
       # Sample COGO input file -- This defines an area.
       # <label> <bearing> <distance>
       P001 S 88:44:56 W 6.7195
       P002 N 33:34:15 W 2.25
       P003 N 23:23:50 W 31.4024
       P004 N 05:04:45 W 25.6981
       P005 N 18:07:25 E 22.2439
       P006 N 27:49:50 E 75.7317
       P007 N 22:56:50 E 87.4482
       P008 N 37:45:15 E 37.7835
       P009 N 46:04:30 E 11.5854
       P010 N 90:00:00 E 8.8201
       P011 N 90:00:00 E 164.1128
       P012 S 48:41:12 E 10.1311
       P013 S 00:25:50 W 255.7652
       P014 N 88:03:13 W 98.8567
       P015 S 88:44:56 W 146.2713
       P016 S 88:44:56 W 18.7164

       Round trip:
          m.cogo -l input=cogo.dat | m.cogo -rl in="-"

       Import as a vector points map:
          m.cogo -l input=cogo.dat | v.in.ascii output=cogo_points x=1 y=2 separator=space

       Shell script to import as a vector line map:
          m.cogo -l input=cogo.dat | tac | awk ’
              BEGIN { FS=" " ; R=0 }
              $1~/\d*\.\d*/ { printf(" %.8f %.8f\n", $1, $2) ; ++R }
              END { printf("L %d\n", R) }’ | tac | \
              v.in.ascii -n format=standard out=cogo_line

       Convert that lines map into an area:
          # Add the -c flag to the above example to close the loop:
          m.cogo -l -c input=cogo.dat | ...
              ...
          v.type input=cogo_line output=cogo_boundary from_type=line to_type=boundary
          v.centroids input=cogo_boundary output=cogo_area
       If  necessary,  snap  the  boundary  closed  with  the  v.clean module.  Use tool=snap and
       thresh=0.0001, or some small value.

SEE ALSO

        v.centroids, v.clean, wxGUI vector digitizer, v.in.ascii, v.type

AUTHOR

       Eric G. Miller

       Last changed: $Date: 2014-12-09 19:39:37 +0100 (Tue, 09 Dec 2014) $

SOURCE CODE

       Available at: m.cogo source code (history)

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