Plotting A Magnetic Anomaly Map from a .grd file with grdread2

Hi,

I want to plot a magnetic anomaly map in Alaska with my data on top of it. I have downloaded the magnetic map from this URL: ftp://ftpext.usgs.gov/pub/cr/co/denver/musette/pub/open-file-reports/ofr-02-0414

Then, I am trying to plot this data on my map by using :

[mx, my]=grdread2('NAmag_origmrg.grd');
pb=surfm(my,mx);

However, after a while I get the following output error:

Error using netcdflib
The NetCDF library encountered an error during execution of 'open' function - 'Unknown file format (NC_ENOTNC)'.

Error in netcdf.open (line 67)
        [varargout{:}] = netcdflib ( 'open', filename, varargin{1} );

Error in grdread2 (line 61)
ncid = netcdf.open(file, 'NC_NOWRITE');

Can anyone help me, please? I do not understand what format it is talking about, I cannot find these lines in the grdread2 function, and I cannot open the file I have downloaded with anything on my computer except by doing this.

Thank you in advance for your help.

Vince

[Sadman Sakib]

Hi, were you able to solve this? I am having the same issue. If you were able to open the .grd file, please share. Thanks!