NAME
grd2xyz - Converting a grdfile to an ASCII or binary table
SYNOPSIS
grd2xyz grdfile [ -H[nrec] ] [ -Rwest/east/south/north[r] [
-S ] [ -Z[flags] ] [ -bo[s] ]
DESCRIPTION
grd2xyz reads a 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 .gmtdefaults 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
The 2-D binary file to be converted.
OPTIONS
-H Output 1 header record based on information in the
grdfile header. Ignored if binary output is selected.
[Default is no header].
-R west, east, south, and north specify the Region of
interest. To specify boundaries in degrees and minutes
[and seconds], use the dd:mm[:ss] format. Append r if
lower left and upper right map coordinates are given
instead of wesn.
-S Suppress output for nodes whose z-value equals NaN
[Default outputs all nodes].
-Z Write a 1-column ASCII [or binary] table. Output will
be organized according to the specified ordering con-
vention 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]. This option only applies to xyz
output; see -Z for z table output.
EXAMPLES
To edit individual values in the 5' by 5' hawaii_grv.grd
file, try
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, try
grd2xyz raw_data.grd -ZTLf > hawaii_grv.b
SEE ALSO
gmtdefaults(l), gmt(l), grdedit(l), xyz2grd(l)