grdpaste − Paste together two .grd files along a common edge.
grdpaste file_a.grd file_b.grd −Goutfile.grd [ −V ] [ −f[i|o]colinfo ]
will combine file_a.grd and file_b.grd into
outfile.grd by pasting them together along their
common edge. Files file_a.grd and file_b.grd
must have the same dx, dy and have one edge in common. If in
doubt, check with grdinfo and use grdcut
and/or grdsample if necessary to prepare the edge
joint. For geographical grids, use −f to handle
One of two files to be pasted together.
The other of two files to be pasted together.
The name for the combined output.
Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
Special formatting of input and/or output columns (time or geographical data). Specify i or o to make this apply only to input or output [Default applies to both]. Give one or more columns (or column ranges) separated by commas. Append T (absolute calendar time), t (relative time in chosen TIME_UNIT since TIME_EPOCH), x (longitude), y (latitude), or f (floating point) to each column or column range item. Shorthand −f[i|o]g means −f[i|o]0x,1y (geographic coordinates).
By default GMT writes out grid as single precision floats in a COARDS-complaint netCDF file format. However, GMT is able to produce grid files in many other commonly used grid file formats and also facilitates so called "packing" of grids, writing out floating point data as 2- or 4-byte integers. To specify the precision, scale and offset, the user should add the suffix =id[/scale/offset[/nan]], where id is a two-letter identifier of the grid type and precision, and scale and offset are optional scale factor and offset to be applied to all grid values, and nan is the value used to indicate missing data. When reading grids, the format is generally automatically recognized. If not, the same suffix can be added to input grid file names. See grdreformat(1) and Section 4.17 of the GMT Technical Reference and Cookbook for more information.
When reading a netCDF file that contains multiple grids, GMT will read, by default, the first 2-dimensional grid that can find in that file. To coax GMT into reading another multi-dimensional variable in the grid file, append ?varname to the file name, where varname is the name of the variable. Note that you may need to escape the special meaning of ? in your shell program by putting a backslash in front of it, or by placing the filename and suffix between quotes or double quotes. The ?varname suffix can also be used for output grids to specify a variable name different from the default: "z". See grdreformat(1) and Section 4.18 of the GMT Technical Reference and Cookbook for more information, particularly on how to read splices of 3-, 4-, or 5-dimensional grids.
Suppose file_a.grd is 150E - 180E and 0 - 30N, and file_b.grd is 150E - 180E, -30S - 0, then you can make outfile.grd which will be 150 - 180 and -30S - 30N by:
grdpaste file_a.grd file_b.grd −G outfile.grd −V −fg
GMT(1), grdcut(1), grdinfo(1), grdsample(1)