PROJ(1) PROJ(1)
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NAME
proj - forward cartographic projection filter
invproj - inverse cartographic projection filter
SYNOPSIS
proj [ -bceEfiIlmorsStTvVwW [ args ] ] [ +args ] file[s]
invproj [ -bceEfiIlmorsStTwW [ args ] ] [ +args ] file[s]
DESCRIPTION
Proj and invproj perform respective forward and inverse transformation
of cartographic data to or from cartesian data with a wide range of
selectable projection functions.
The following control parameters can appear in any order:
-b Special option for binary coordinate data input and output
through standard input and standard output. Data is assumed to
be in system type double floating point words. This option is to
be used when proj is a son process and allows bypassing
formatting operations.
-i Selects binary input only (see -b option).
-I alternate method to specify inverse projection. Redundant when
used with invproj.
-o Selects binary output only (see -b option).
-ta A specifies a character employed as the first character to denote
a control line to be passed through without processing. This
option applicable to ascii input only. (# is the default value).
-e string
String is an arbitrary string to be output if an error is
detected during data transformations. The default value is:
*\t*. Note that if the -b, -i or -o options are employed, an
error is returned as HUGE_VAL value for both return values.
-E causes the input coordinates to be copied to the output line
prior to printing the converted values.
-l[p|P|=|e|u|d]id
List projection identifiers with -l, -lp or -lP (expanded) that
can be selected with +proj. -l=id gives expanded description of
projection id. List ellipsoid identifiers with -le, that can be
selected with +ellps, -lu list of cartesian to meter conversion
factors that can be selected with +units or -ld list of datums
that can be selected with +datum.
-r This options reverses the order of the expected input from
longitude-latitude or x-y to latitude-longitude or y-x.
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-s This options reverses the order of the output from x-y or
longitude-latitude to y-x or latitude-longitude.
-S Causes estimation of meridinal and parallel scale factors, area
scale factor and angular distortion, and maximum and minimum
scale factors to be listed between <> for each input point. For
conformal projections meridinal and parallel scales factors will
be equal and angular distortion zero. Equal area projections
will have an area factor of 1.
-m mult
The cartesian data may be scaled by the mult parameter. When
processing data in a forward projection mode the cartesian output
values are multiplied by mult otherwise the input cartesian
values are divided by mult before inverse projection. If the
first two characters of mult are 1/ or 1: then the reciprocal
value of mult is employed.
-f format
Format is a printf format string to control the form of the
output values. For inverse projections, the output will be in
degrees when this option is employed. The default format is
"%.2f" for forward projection and DMS for inverse.
-[w|W]n
N is the number of significant fractional digits to employ for
seconds output (when the option is not specified, -w3 is
assumed). When -W is employed the fields will be constant width
and with leading zeroes.
-v causes a listing of cartographic control parameters tested for
and used by the program to be printed prior to input data.
Should not be used with the -T option.
-V This option causes an expanded annotated listing of the
characteristics of the projected point. -v is implied with this
option.
-T ulow,uhi,vlow,vhi,res[,umax,vmax]
This option creates a set of bivariate Chebyshev polynomial
coefficients that approximate the selected cartographic
projection on stdout. The values low and hi denote the range of
the input where the u or v prefixes apply to respective
longitude-x or latitude-y depending upon whether a forward or
inverse projection is selected. Res is an integer number
specifying the power of 10 precision of the approximation. For
example, a res of -3 specifies an approximation with an accuracy
better than .001. Umax, and vmax specify maximum degree of the
polynomials (default: 15). See also: fproj(1).
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The +args run-line arguments are associated with cartographic
parameters and usage varies with projection and for a complete
description see Cartographic Projection Procedures for the UNIX
Environment-A User's Manual ) and supplementary documentation for
Release 4.
Additional projection control parameters may be contained in two
auxiliary control files: the first is optionally referenced with the
+init=file:id and the second is always processed after the name of the
projection has been established from either the run-line or the
contents of +init file. The environment parameter PROJ_LIB
establishes the default directory for a file reference without an
absolute path. This is also used for supporting files like datum
shift files.
One or more files (processed in left to right order) specify the
source of data to be transformed. A - will specify the location of
processing standard input. If no files are specified, the input is
assumed to be from stdin. For ASCII input data the two data values
must be in the first two white space separated fields and when both
input and output are ASCII all trailing portions of the input line are
appended to the output line.
Input geographic data (longitude and latitude) must be in DMS format
and input cartesian data must be in units consistent with the
ellipsoid major axis or sphere radius units. Output geographic
coordinates will be in DMS (if the -w switch is not employed) and
precise to 0.001" with trailing, zero-valued minute-second fields
deleted.
EXAMPLE
The following script
proj +proj=utm +lon_0=112w +ellps=clrk66 -r <<EOF
45d15'33.1" 111.5W
45d15.551666667N -111d30
+45.25919444444 111d30'000w
EOF
will perform UTM forward projection with a standard UTM central
meridian nearest longitude 112oW. The geographic values of this
example are equivalent and meant as examples of various forms of DMS
input. The x-y output data will appear as three lines of:
460769.27 5011648.45
OTHER PROGRAMS
The proj program is limited to converting between geographic and
projection coordinates within one datum.
The cs2cs program operates similarly, but allows translation between
any pair of definable coordinate systems, including support for datum
translation.
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The nad2nad program provides for translation between NAD27 and NAD83
(also available in cs2cs) in a convenient manner.
The geod program provides the ability to compute geodesic (Great
Circle) computations.
SEE ALSO
cs2cs(1U), nad2nad(1U), geod(1U), pj_init(3U),
Cartographic Projection Procedures for the UNIX Environment-A User's
Manual, (Evenden, 1990, Open-file report 90-284).
Map Projections Used by the U. S. Geological Survey (Snyder, 1984,
USGS Bulletin 1532).
Map Projections-A Working Manual (Snyder, 1988, USGS Prof. Paper
1395).
An Album of Map Projections (Snyder & Voxland, 1989, USGS Prof. Paper
1453).
HOME PAGE
http://www.remotesensing.org/proj
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