Provided by: gmt_4.5.11-1build1_amd64 bug


       grd2xyz - Converting grid file(s) to ASCII or binary data


       grd2xyz    grdfiles    [    -E[f][nodata]   ]   [   -H[i][nrec]   ]   [   -Nnodata   ]   [
       -Rwest/east/south/north[r]  ]  [  -S[r]  ]  [  -V  ]  [  -W[weight]  ]  [  -Z[flags]  ]  [
       -bo[s|S|d|D[ncol]|c[var1/...]] ] [ -fcolinfo ]


       grd2xyz  reads  one or more binary 2-D grid files 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 use --D_FORMAT=value on the
       command line, 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 -E or -Z

              Names of 2-D binary grid files to be converted.  (See GRID FILE FORMATS below.)


       -E     Output an ESRI ArcInfo ASCII interchange grid format  file.   Append  f  for  float
              output  [Default  is  integer].  Append nodata which will be used wherever the grid
              value equals NaN [-9999].

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

       -N     Output this z-value where the latter equals NaN [Default writes NaN].

       -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[][W|E|S|N] format.  Append r if lower left
              and upper right map coordinates are given instead of w/e/s/n.  The  two  shorthands
              -Rg and -Rd stand for global domain (0/360 and -180/+180 in longitude respectively,
              with -90/+90 in latitude).  Alternatively, specify the name  of  an  existing  grid
              file  and  the  -R  settings  (and grid spacing, if applicable) are copied from the
              grid.  For calendar  time  coordinates  you  may  either  give  (a)  relative  time
              (relative  to  the  selected  TIME_EPOCH and in the selected TIME_UNIT; append t to
              -JX|x), or (b) 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  exactly  as  indicated
              (however, input, output and plot formats are customizable; see gmtdefaults).  Using
              the -R option will select a subsection of the grid. If this subsection exceeds  the
              boundaries of the grid, only the common region will be output.

       -S     Suppress  output  for  nodes  whose z-value equals NaN [Default outputs 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

       -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 organized 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  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 [architecture-dependent!]
              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  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  3].   This  option  only
              applies to xyz output; see -Z for z table output.

       -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).   See  also
              TIME COORDINATES below.


       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.


       GMT  is  able  to  recognize  many  of the commonly used grid file formats, as well as the
       precision, scale and offset of the values contained in the grid file.  When  GMT  needs  a
       little help with that, you can add the suffix =id[/scale/offset[/nan]], where id is a two-
       letter identifier of the grid type and precision, and scale and offset are optional  scale
       factor  and offset to be applied to all grid values, and nan is the value used to indicate
       missing data.  See grdreformat(1) and Section 4.17 of  the  GMT  Technical  Reference  and
       Cookbook for more information.

       When  reading  a  netCDF file that contains multiple grids, GMT will read, by default, the
       first 2-dimensional grid that can find in that file. To  coax  GMT  into  reading  another
       multi-dimensional  variable  in  the  grid  file,  append ?varname to the file name, where
       varname is the name of the variable. Note that you may need to escape the special  meaning
       of  ?  in  your  shell  program  by  putting a backslash in front of it, or by placing the
       filename and suffix between quotes or double quotes.  See grdreformat(1) and Section  4.18
       of  the  GMT Technical Reference and Cookbook for more information, particularly on how to
       read splices of 3-, 4-, or 5-dimensional grids.


       Time coordinates in netCDF grids, be it the x, y, or z coordinate, will be  recognized  as
       such.  The variable's unit attribute is parsed to determine the unit and epoch of the time
       coordinate in the grid.  Values are then converted to the internal time  system  specified
       by  TIME_UNIT and TIME_EPOCH in the .gmtdefaults file or on the command line.  The default
       output is relative time in that time system, or absolute time when using the option  -f0T,
       -f1T, or -f2T for x, y, or z coordinate, respectively.


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

       grd2xyz hawaii_grv.grd >

       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


       gmtdefaults(1), GMT(1), grdedit(1), xyz2grd(1)