PROJ(1) PROJ(1)
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 bypass-
ing formatting operations.
-i Selects binary input only (see -b
option).
-I alternate method to specify inverse pro-
jection. 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 out-
put 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.
-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 paral-
lel scale factors, area scale factor and
angular distortion, and maximum and mini-
mum scale factors to be listed between <>
for each input point. For conformal pro-
jections meridinal and parallel scales
factors will be equal and angular distor-
tion 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 oth-
erwise the input cartesian values are
divided by mult before inverse projec-
tion. 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 con-
trol 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 poly-
nomials (default: 15). See also:
fproj(1).
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 auxilliary 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 estab-
lished 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 trans-
formed. A - will specify the location of pro-
cessing standard input. If no files are speci-
fied, 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 geo-
graphic 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 stan-
dard UTM central meridian nearest longitude
112°W. 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 coor-
dinate systems, including support for datum
translation.
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
geodetic (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 (Synder, 1988,
USGS Prof. Paper 1395).
An Album of Map Projections (Snyder & Voxland,
1989, USGS Prof. Paper 1453).
HOME PAGE
http://www.remotesensing.org/proj
2000/03/21 Rel. 4.4 PROJ(1)
