[Proj] pms finally comes to project projection library
Gerald I. Evenden
geraldi.evenden at gmail.com
Fri May 15 11:53:46 PDT 2009
The prime meridian system offset option has finally been added to the
projection library. There are two ways to use it:
1. use the list of "standard" prime meridians from the list below:
sproj -l pms
Athens : 23d42'58.815"E
Bern : 7d26'22.5"E
Bogota : 74d04'51.3"W
Brussels : 4d22'4.71"E
Ferro : 17d40'W
Greenwich : 0dE
Jakarta : 106d48'27.79"E
Lisbon : 9d07'54.862"W
Madrid : 3d41'16.58"W
Oslo : 10d43'22.5"E
Paris : 2d20'14.025"E
Rome : 12d27'8.4"
Stockholm : 18d3'29.8"E
and using as
sproj proj=poly ellps=wgs84 pms=ferro
List spiked from Warmerdams proj-4.6.1 and unverified.
2, or by specifying your own value such as:
sproj proj=poly ellps=wgs84 pms=2d30.7W
The pms offset only applies to only correcting the data to the Greenwich
meridian and any longitude values related to projection definition are in the
coordinate system of the original system. This is demonstrated below:
sproj proj=tmerc ellps=wgs84 lon_0=5 pms=7d33\'14 -I <<EOF
0 0
EOF
12d33'14.000"E 0d00'00.000"N
Using the projection inverse shows shows more readily where the CM ends up.
sproj is a basic, no frills projection rooutine:
sproj -h
Short Cartographic Projection Computer v. 1.0
Compute forward or inverse cartographic projections
Usage: sproj [OPTIONS] [projection options]
A program to compute forward or inverse cartographic projection.
-h, --help Print help and exit
--detailed-help Print help, including all details and hidden
options, and exit
-V, --version Print version and exit
-I, --inverse Inverse projection (default=off)
-r, --revin reverse order of input to phi-lam or y-x
(default=off)
-R, --revout reverse order of output to y-x or phi-lam
(default=off)
-f, --format=C_format_str output format
-l, --list=ENUM list options (possible values="proj",
"ellps", "pms", "units" default=`proj')
-P, --longproj[=proj_id] detail projection list
Data I/O is through stdin/out and geographic data may be in either DMS or
colon format. User can format colon for output. I will probably flesh sproj
out more in the future.
I should be able to get this whole ball of wax on my web site by Sunday, 17
May, barring any more autoconf, el al disasters. :-(
--
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist
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