NAME
m.proj2 - Calculates conversion coordinates for geographic
positions.
(GRASS Map Development Program)
SYNOPSIS
m.proj2 [inproj=name[,name,...]] [outproj=name[,name,...]] [input=name]
[output=name]
Parameters:
- inproj
- Comma separated input projection parameters
- outproj
- Comma separated output projection parameters
- input
- Input coordinate file
- output
- Output coordinate file
DESCRIPTION
This program allows a user to (optionally interactively) convert coordinates
from one projection to another. It allows a user to convert coordinates from
a file, writing to a file.
Note: The program does not transform GRASS files, it is designed to
determine coordinate values on an individual position.
The map projections currently supported are listed in etc/projections file.
Each of the above projections (with the exception of State Plane) can be
computed with the spheroids listed in etc/ellipse.table file.
INPUT FILE FORMAT
- When reading from a file of LATITUDE/LONGITUDE data the
file will contain three (2) columns of information:
- the first column - latitude - in degrees minutes seconds,
- the second column - longitude - in degrees minutes seconds,
For example:
+40 36 31.4563 -87 2 7.8193
40n 36 31.4563 87w 2 7.8193
- When reading from a file of PROJECTION COORDINATES data the
file will contain three (2) columns of information:
- the first column - easting - ground coordinates
- the second column - northing - ground coordinates
For example:
500000.00 4496918.64
-424489.11 1908736.13
USAGE EXAMPLE
For example, if desired to transform points from UTM projection to the
Gauss-Krüger Grid System it can be done by running:
m.proj2 inproj="proj=utm,name=utm,a=6378137.0,es=0.006694380,\
zone=32,unfact=1.0" outproj="proj=tmerc,name=tmerc,\
a=6377397.155,es=0.0066743720,lat_0=0.0,lon_0=9.0,k=1.0,\
x_0=3500000.0" input=utm.coord output=new.gk.coord
Projection parameters have to be provided, in above case: "proj"
(projection type), "name" (projection name), "a" (ellipsoid: equatorial
radius), "es" (ellipsoid: eccentricity squared), "zone" (zone for the
area), "unfact" (conversion factor from meters to other units, e.g. feet),
"lat_0" (standard parallel), "lon_0" (central meridian), "k" (scale
factor) and "x_0" (false easting). Sometimes false northing is needed which
is coded as "y_0". Internally, the underlying PROJ 4 projection library
performs an inverse projection to latitude-longitude and then projects the
coordinate list to the target projection.
Note: NO column headings are required, just the numbers.
BUGS
Datum transformations are not yet supported.
References:
[1]Evenden, G.I. (1990) Cartographic projection procedures for
the UNIX environment - a user's manual. USGS Open-File Report 90-284
(Also see Interim Report and 2nd Interim Report on Release 4, Evenden 1994).
SEE ALSO
m.proj,
s.proj,
v.proj,
g.setproj,
i.rectify,
i.rectify3,
r.support,
r.stats,
s.sample,
s.surf.idw,
s.surf.rst
AUTHOR
Bob Covill, code based on m.proj
Last changed: $Date$