---
name: "grd2xyz"
section: "1"
platform: "linux"
package: "gmt-manpages"
version: "3.4-1"
release: "Debian 3.0 (Woody)"
platforms: ["linux"]
url: "https://new.carta.tech/grd2xyz"
---

# grd2xyz(1)

Converting a grdfile to an ASCII or binary table

## 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**\[**s**\] \]

## 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*(l), *gmt*(l), *grdedit*(l), *xyz2grd*(l)