NAME
grd2xyz - Converting a grdfile to an ASCII or binary table
SYNOPSIS
grd2xyz grdfile [ -H[nrec] ] [ -L ] [ -Rwest/east/south/north[r] [ -S[r
] [ -V ] [ -Z[flags] ] [ -bo[s][n] ]
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 .gmtde-
faults 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].
-L Indicates that the x values are longitudes (necessary for -: to
work).
-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 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"].
-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.
-O Selects Overlay plot mode [Default initializes a new plot sys-
tem]. This option only applies to xyz output; see -Z for z ta-
ble 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)
GMT3.4.6 1 Jan 2005 GRD2XYZ(l)
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