NAME

       segy2grd - Converting SEGY file to grid file format

SYNOPSIS

       segy2grd  segyfile -Ggrdfile -Ixinc[unit][=|+][/yinc[unit][=|+]] -Rwest/east/south/north[r] [ -A[n|z] ] [
       -Dxname/yname/zname/scale/offset/title/remark ] [ -F ]   [ -Nnodata ] [ -S[zfile] ] [ -V ] [ -Z[flags]  ]
       [ -:[i|o] ] [ -bi[s|S|d|D[ncol]|c[var1/...]] ]

DESCRIPTION

       segy2grd  reads  an IEEE SEGY file and creates a binary grid file. Either a simple mapping (equivalent to
       xyz2grd -Z) or a more complicated averaging where a particular grid cell includes values from  more  than
       one  sample  in  the  SEGY file can be done.  segy2grd will report if some of the nodes are not filled in
       with data. Such unconstrained nodes are set to a value specified by the user  [Default  is  NaN].   Nodes
       with more than one value will be set to the average value.

       segyfile is an IEEE floating point SEGY file. Traces are all assumed to start at 0 time/depth.

       -G     grdfile is the name of the binary output grid file.

       -I     x_inc  [and  optionally  y_inc] is the grid spacing. Append m to indicate minutes or c to indicate
              seconds.

       -R     west, east, south, and north specify the Region of interest, 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 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.

OPTIONS

       -A     Add up multiple values that belong to the same node (same as -Az).  Append n to simply  count  the
              number  of  data  points  that were assigned to each node.  [Default (no -A option) will calculate
              mean value]. Not used for simple mapping.

       -D     Give values for xname, yname, zname, scale, offset, title, and remark.  To  leave  some  of  these
              values untouched, specify = as the value.

       -F     Force pixel registration [Default is grid registration].

       -N     No data. Set nodes with no input sample to this value [Default is NaN].

       -S     set  variable  spacing  header  is c for cdp, o for offset, b<number> for 4-byte float starting at
              byte number If -S not set, assumes even spacing of samples at the dx, dy supplied with -I

       -L     Override number of samples in each trace

       -X     applies scalar x-scale to coordinates in trace header to match the coordinates specified in -R

       -Y     Specifies sample interval as s_int if incorrect in the SEGY file

       -M     Fix number of traces to read in. Default tries to read 10000 traces.   -M0  will  read  number  in
              binary header, -Mn will attempt to read only n traces.

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

       EXAMPLES
              To create a grid file from an even spaced SEGY file test.segy, try

              segy2grd test.segy -I 0.1/0.1 -G test.grd -R 198/208/18/25 -V

              Note  that  this will read in 18-25s (or km) on each trace, but the first trace will be assumed to
              be at X=198

              To create a grid file from the SEGY file test.segy, locating traces according to the  CDP  number,
              where there are 10 CDPs per km and the sample interval is 0.1, try

              segy2grd test.segy  -G test.grd -R 0/100/0/10 -I 0.5/0.2 -V -X 0.1  -Y 0.1

              Because  the  grid  interval is larger than the SEGY file sampling, the individual samples will be
              averaged in bins

SEE ALSO

       GMT(1), grd2xyz(1), grdedit(1), pssegy(1)

GMT 4.5.11                                         5 Nov 2013                                     SEGY2GRD(1gmt)