NAME¶
grd2xyz - Converting a grdfile to an ASCII or binary table
SYNOPSIS¶
grd2xyz grdfile [
-H[
nrec] ] [
-L ] [
-R west/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 .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].
- -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 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 "silently"].
- -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):
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(1gmt),
gmt(1gmt),
grdedit(1gmt),
xyz2grd(1gmt)