Z=GRDREAD2('filename.grd') will return the data as a matrix in Z
[X,Y,Z]=GRDREAD2('filename.grd') will also return X and Y vectors suitable for use in Matlab commands such as IMAGE or CONTOUR.
e.g., imagesc(X,Y,Z); axis xy
This function will load COARDS compliant netCDF grdfiles, the standard format in GMT 4 and later, as well as GMT v3 netCDF formats. The data matrix Z will have a MATLAB data type appropriate to the data type used in the netCDF file. Although both gridline and pixel registered grids can be read, pixel registration will be converted to gridline registration for the x- and y-vectors in MATLAB.
This program currently does little error checking and makes some assumptions about the content and structure of netCDF files that may not always be valid (especially in grids created in other software, even if they can be read by GMT). It has been tested on grid files created in a number of GMT versions since 3.1, using MATLAB R2009b in OS X, Linux and Windows, and in R2008b in OS X. It will not work with any binary grid file formats. It is the responsibility of the user to determine whether this program is appropriate for any given task.
For more information on GMT grid file formats, see:
GMT (Generic Mapping Tools) was developed by Paul Wessel and Walter H. F. Smith
See also GRDWRITE2, GRDINFO2