NAME

       grd2xyz - Converting grdfile(s) to ASCII or binary data

SYNOPSIS

       grd2xyz  grdfile(s)  [ -H[nrec] ] [ -L ] [ -Rwest/east/south/north[r] [
       -S[r ] [ -V ] [ -W[weight] ] [ -Z[flags] ] [ -bo[s][n] ] [  -f[i|o]col-
       info ]

DESCRIPTION

       grd2xyz  reads  one  or  more  binary  2-D  grdfile and writes out xyz-
       triplets in ASCII [or binary] format to standard  output.   Modify  the
       precision  of the ASCII output format by editing the D_FORMAT parameter
       in your .gmtdefaults4 file, or choose binary  output  using  single  or
       double  precision storage. As an option you may output z-values without
       the (x,y) in a number of formats, see -Z below.

       grdfile
              Names of 2-D binary grd files to be converted.

OPTIONS

       -H     Output 1 header record based on information in the first grdfile
              header.   Ignored  if  binary output is selected. [Default is no
              header].

       -L     Indicates that the x values are longitudes (necessary for -:  to
              work).

       -R     xmin,  xmax,  ymin, and ymax specify the Region of interest. For
              geographic regions,  these  limits  correspond  to  west,  east,
              south,  and north and you may specify them in decimal degrees or
              in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r  if  lower  left
              and  upper  right map coordinates are given instead of wesn. The
              two shorthands  -Rg  -Rd  stand  for  global  domain  (0/360  or
              -180/+180  in longitude respectively, with -90/+90 in latitude).
              For calendar time coordinates you may either give relative  time
              (relative  to  the  selected  TIME_EPOCH  and  in  the  selected
              TIME_UNIT; append t to -JX|x), or  absolute  time  of  the  form
              [date]T[clock]  (append  T  to  -JX|x). At least one of date and
              clock must be present; the T is always required. The date string
              must  be  of  the form [-]yyyy[-mm[-dd]] (Gregorian calendar) or
              yyyy[-Www[-d]] (ISO week calendar), while the clock string  must
              be  of  the form hh:mm:ss[.xxx]. The use of delimiters and their
              type and positions must be as indicated  (however,  input/output
              and plotting formats are flexible).

       -S     Suppress output for nodes whose z-value equals NaN [Default out-
              puts all nodes].  Append r to  reverse  the  suppression,  i.e.,
              only output the nodes whose z-value equals NaN.

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

       -W     Write out x,y,z,w, where w is the supplied weight (or 1  if  not
              supplied) [Default writes x,y,z only].

       -Z     Write  a  1-column ASCII [or binary] table. Output will be orga-
              nized according to the specified ordering  convention  contained
              in  flags.   If data should be written by rows, make flags start
              with T(op) if first row is y = ymax or B(ottom) if first row  is
              y  =  ymin.  Then,  append L or R to indicate that first element
              should start at left or right end of row.  Likewise  for  column
              formats:  start  with  L or R to position first column, and then
              append T or B to position first element in a row.  For  gridline
              registered  grids:  If  grid  is periodic in x but the outcoming
              data should not contain the (redundant)  column  at  x  =  xmax,
              append x. For grid periodic in y, skip writing the redundant row
              at y = ymax by appending  y.  If  the  byte-order  needs  to  be
              swapped,  append w. Select one of several data types (all binary
              except a):

                      a ASCII representation
                      c signed 1-byte character
                      u unsigned 1-byte character
                      h short 2-byte integer
                      i 4-byte integer
                      l long (4- or 8-byte) integer
                      f 4-byte floating point single precision
                      d 8-byte floating point double precision

              Default format is scanline orientation of ASCII numbers:  -ZTLa.
              Note that -Z only applies to 1-column output.

       -bo    Selects binary output. Append s for single precision [Default is
              double].  Append n for the  number  of  columns  in  the  binary
              file(s).
              This  option only applies to xyz output; see -Z for z table out-
              put.

       -f     Special formatting of input and output  columns  (time  or  geo-
              graphical  data)  Specify  i(nput)  or o(utput) [Default is both
              input and output].  Give one or more columns (or column  ranges)
              separated by commas.  Append T (Absolute calendar time), t (time
              relative to chosen TIME_EPOCH), x (longitude), y  (latitude),  g
              (geographic coordinate), or f (floating point) to each column or
              column range item.

EXAMPLES

       To edit individual values in the 5’ by 5’ hawaii_grv.grd file, dump the
       .grd to ASCII:

       grd2xyz hawaii_grv.grd > hawaii_grv.xyz

       To  write a single precision binary file without the x,y positions from
       the file raw_data.grd file, using scanline orientation, run

       grd2xyz raw_data.grd -ZTLf > hawaii_grv.b

SEE ALSO

       gmtdefaults(l), gmt(l), grdedit(l), xyz2grd(l)



GMT4.0                            1 Oct 2004                        GRD2XYZ(l)