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).
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.
m.cogo -l in=cogo.dat
# 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
Available at: m.cogo source code (history)
Latest change: Thursday Jan 26 14:10:26 2023 in commit: cdd84c130cea04b204479e2efdc75c742efc4843
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