Provided by: gmt_4.5.11-1build1_amd64 bug

NAME

       project  -  project  data  along  a  line  or  great  circle, generate a profile track, or
       translate coordinates.

SYNOPSIS

       project [ infile ] -Ccx/cy [ -Aazimuth ] [ -Dd|g ] [ -Ebx/by ] [ -Fflags ] [  -Gdist  ]  [
       -H[i][nrec]  ]  [  -L[w][l_min/l_max]  ]  [  -N  ]  [  -Q  ]  [  -S ] [ -Tpx/py ] [ -V ] [
       -Ww_min/w_max ] [ -:[i|o] ] [ -b[i|o][s|S|d|D[ncol]|c[var1/...]] ] [  -f[i|o]colinfo  ]  [
       -m[i|o][flag] ]

DESCRIPTION

       project  reads  arbitrary  (x, y[, z]) data from standard input [or infile ] and writes to
       standard output any combination of (x, y, z, p, q, r, s), where (p, q) are the coordinates
       in  the projection, (r, s) is the position in the (x, y) coordinate system of the point on
       the profile (q = 0 path) closest to (x, y), and z is all remaining columns  in  the  input
       (beyond the required x and y columns).  Alternatively, project may be used to generate (r,
       s, p) triples at equal increments dist along a profile.  In this case  (  -G  option),  no
       input  is  read.  Projections are defined in any (but only) one of three ways: (Definition
       1)  By a Center -C and an Azimuth -A in degrees clockwise from North.  (Definition 2)   By
       a Center -C and end point E of the projection path -E.  (Definition 3)  By a Center -C and
       a roTation pole position -T.  To spherically project data along a great  circle  path,  an
       oblique  coordinate  system is created which has its equator along that path, and the zero
       meridian through the Center.  Then the oblique longitude (p) corresponds to  the  distance
       from  the  Center  along the great circle, and the oblique latitude (q) corresponds to the
       distance perpendicular to the great circle  path.   When  moving  in  the  increasing  (p)
       direction,  (toward  B or in the azimuth direction), the positive (q) direction is to your
       left.  If a Pole has been specified, then the positive (q) direction is toward the pole.
       To specify an oblique projection, use the -T option to set the Pole.  Then the equator  of
       the  projection  is  already  determined  and  the  -C  option is used to locate the p = 0
       meridian.  The Center cx/cy will be taken as a point through which  the  p  =  0  meridian
       passes.  If you do not care to choose a particular point, use the South pole (ox = 0, oy =
       -90).
       Data can be selectively windowed by using the -L and -W  options.   If  -W  is  used,  the
       projection Width is set to use only points with w_min < q < w_max.  If -L is set, then the
       Length is set to use only those points with l_min < p < l_max.  If the -E option has  been
       used  to  define  the  projection,  then  -Lw  may be selected to window the length of the
       projection to exactly the span from O to B.
       Flat Earth (Cartesian) coordinate transformations can also be made.  Set -N  and  remember
       that azimuth is clockwise from North (the y axis), NOT the usual cartesian theta, which is
       counterclockwise from the x axis.  azimuth = 90 - theta.
       No assumptions are made regarding the units for x, y, r, s,  p,  q,  dist,  l_min,  l_max,
       w_min,  w_max.  If -Q is selected, map units are assumed and x, y, r, s must be in degrees
       and p, q, dist, l_min, l_max, w_min, w_max will be in km.
       Calculations of specific great-circle and  geodesic  distances  or  for  back-azimuths  or
       azimuths are better done using mapproject.
       project  is  CASE  SENSITIVE.   Use  UPPER CASE for all one-letter designators which begin
       optional arguments.  Use lower case for the xyzpqrs letters in -flags.

       -C     cx/cy sets the origin of the projection, in Definition 1 or 2.  If Definition 3  is
              used (-T), then cx/cy are the coordinates of a point through which the oblique zero
              meridian (p = 0) should pass.

OPTIONS

       infile name of ASCII (or binary, see -bi) file(s) with 2 or more columns holding (x,y,[z])
              data values.  If no filenames are given, project will read from standard input.  If
              the -G option is selected, no input data are read.

       -F     Specify your desired output using any combination of xyzpqrs, in any order.  Do not
              space  between  the letters.  Use lower case.  The output will be ASCII (or binary,
              see -bo) columns of values corresponding to xyzpqrs [Default].  If both  input  and
              output are using ASCII format then the z data are treated as textstring(s).  If the
              -G option is selected, the output will be rsp.

       -A     azimuth defines the azimuth of the projection (Definition 1).

       -D     Set the location of the Discontinuity in longitude (r coordinate).  -Dd will  place
              the  discontinuity  at  the  Dateline,  (-180  <  r  <  180);  -Dg will place it at
              Greenwich, (0 < r < 360).  Default usually falls at dateline due to atan2 calls.

       -E     bx/by defines the end point of the projection path (Definition 2).

       -G     dist Generate mode.  No input is read.  Create (r, s, p) output points  every  dist
              units of p.  See -Q option.

       -H     Input  file(s) has header record(s).  If used, the default number of header records
              is N_HEADER_RECS.  Use -Hi if only input data should have header  records  [Default
              will  write  out header records if the input data have them]. Blank lines and lines
              starting with # are always skipped.

       -L     Length controls.  Project only those points whose p coordinate is within l_min <  p
              < l_max.  If -E has been set, then you may use -Lw to stay within the distance from
              C to E.

       -N     Flat Earth.  Make a Cartesian coordinate transformation  in  the  plane.   [Default
              uses spherical trigonometry.]

       -Q     Map  type  units, i.e., project assumes x, y, r, s are in degrees while p, q, dist,
              l_min, l_max, w_min, w_max are in km.  If -Q is not set, then all these are assumed
              to be in the same units.

       -S     Sort the output into increasing p order.  Useful when projecting random data into a
              sequential profile.

       -T     px/py sets the position of the roTation pole of the projection.  (Definition 3).

       -V     Selects verbose mode, which will send progress  reports  to  stderr  [Default  runs
              "silently"].

       -W     Width controls.  Project only those points whose q coordinate is within w_min < q <
              w_max.

       -:     Toggles between (longitude,latitude) and (latitude,longitude) input and/or  output.
              [Default  is  (longitude,latitude)].   Append i to select input only or o to select
              output only.  [Default affects both].

       -bi    Selects binary input.  Append s for  single  precision  [Default  is  d  (double)].
              Uppercase  S or D will force byte-swapping.  Optionally, append ncol, the number of
              columns in your binary input file if it exceeds the columns needed by the  program.
              Or  append  c  if  the  input  file  is netCDF. Optionally, append var1/var2/... to
              specify the variables to be read.  [Default is 2 input columns].

       -bo    Selects binary output.  Append s for single  precision  [Default  is  d  (double)].
              Uppercase  S or D will force byte-swapping.  Optionally, append ncol, the number of
              desired columns in your binary output file.  [Default is given by -F or -G].

       -f     Special formatting of input and/or output  columns  (time  or  geographical  data).
              Specify  i  or  o  to  make  this apply only to input or output [Default applies to
              both].  Give one or more columns (or column ranges) separated by commas.  Append  T
              (absolute calendar time), t (relative time in chosen TIME_UNIT since TIME_EPOCH), x
              (longitude), y (latitude), or f (floating point) to each  column  or  column  range
              item.  Shorthand -f[i|o]g means -f[i|o]0x,1y (geographic coordinates).

       -m     Multiple  segment  file(s).  Segments are separated by a special record.  For ASCII
              files the first character must be flag [Default is  '>'].   For  binary  files  all
              fields  must  be  NaN  and -b must set the number of output columns explicitly.  By
              default the -m setting applies to both input and output.  Use -mi and -mo  to  give
              separate settings to input and output.

ASCII FORMAT PRECISION

       The  ASCII  output  formats  of  numerical  data  are  controlled  by  parameters  in your
       .gmtdefaults4   file.    Longitude   and   latitude    are    formatted    according    to
       OUTPUT_DEGREE_FORMAT,  whereas other values are formatted according to D_FORMAT.  Be aware
       that the format in effect can lead to loss of precision in the output, which can  lead  to
       various problems downstream.  If you find the output is not written with enough precision,
       consider switching to binary output (-bo if available) or specify more decimals using  the
       D_FORMAT setting.

EXAMPLES

       To generate points every 10km along a great circle from 10N,50W to 30N,10W:

       project -C-50/10 -E-10/30 -G 10 -Q > great_circle_points.xyp

       (Note that great_circle_points.xyp could now be used as input for grdtrack, etc. ).

       To  project  the shiptrack gravity, magnetics, and bathymetry in c2610.xygmb along a great
       circle through an origin at 30S, 30W, the great circle having an azimuth of  N20W  at  the
       origin,  keeping only the data from NE of the profile and within +/- 500 km of the origin,
       run:

       project c2610.xygmb -C-30/-30 -A-20 -W-10000/0 -L-500/500 -F pz -Q > c2610_projected.pgmb

       (Note in this example that -W-10000/0 is used to admit any value with a large  negative  q
       coordinate.  This will take those points which are on our right as we walk along the great
       circle path, or to the NE in this example.)

       To make a Cartesian coordinate transformation of mydata.xy so that the new  origin  is  at
       5,3 and the new x axis (p) makes an angle of 20 degrees with the old x axis, use:

       project mydata.xy -C 5/3 -A 70 -F pq > mydata.pq

       To  take data in the file pacific.lonlat and transform it into oblique coordinates using a
       pole from the hotspot reference frame and placing the oblique zero meridian (p =  0  line)
       through Tahiti, run:

       project pacific.lonlat -T-75/68 -C-149:26/-17:37 -F pq > pacific.pq

       Suppose that pacific_topo.grd is a grid file of bathymetry, and you want to make a file of
       flowlines in the hotspot reference frame.  If you run:

       grd2xyz pacific_topo.grd | project -T-75/68 -C 0/-90 -F  xyq  |  xyz2grd  -Retc  -Ietc  -C
       flow.grd

       then  flow.grd  is  a  file  in  the  same area as pacific_topo.grd, but flow contains the
       latitudes about the pole of the projection.  You now can use  grdcontour  on  flow.grd  to
       draw lines of constant oblique latitude, which are flow lines in the hotspot frame.

       If you have an arbitrarily rotation pole px/py and you would like to draw an oblique small
       circle on a map, you will first need to make a file with the oblique coordinates  for  the
       small  circle  (i.e.,  lon = 0-360, lat is constant), then create a file with two records:
       the north pole (0/90) and the origin (0/0), and find what their  oblique  coordinates  are
       using your rotation pole.  Now, use the projected North pole and origin coordinates as the
       rotation pole and center, respectively, and project your file as in  the  pacific  example
       above.  This gives coordinates for an oblique small circle.

SEE ALSO

       fitcircle(1), GMT(1), mapproject(1), grdproject(1)