Surfer Grid import/export

Import and export GS ASCII (GRD files) from and to Golden Software Applications like Surfer and Grap

Description

Surfer Grid, import/export.

Matlab <-> Golden Software Surfer and Grapher

The pack contains two simple routines: grd_write.m and grd_read.m. They communicate Matlab with Golden Software Surfer by the GRD file format (ASCII version).

grd_write(matrix,xmin,xmax,ymin,ymax,namefile)
    Input:
         matrix = matrix to export
         xmin,xmax,ymin,ymax = grid limits
         namefile = name of the file to be written (include ".grd" extension)
    Output:
         grd file in current directory

[matrix xmin xmax ymin ymax]=grd_read(name of file)
    Input:
         nomarch = name of the file to be read, including ".grd" extension
    Output:
         matrix = matrix of the read data
         xmin xmax ymin ymax = grid limits

* NOTE: Previous version of grd_read worked only with files saved in Surfer (or Grapher), but now is SOLVED. It runs faster also.

Example of use:

Creation of a matrix in Matlab:

x=linspace(-4,4,100);
y=linspace(-5,5,100);
[X,Y]=meshgrid(x,y);
Z=cos(sqrt(X.^2+Y.^2));

Export to surfer:

grd_write(Z,min(x),max(x),min(y),max(y),'example.grd')

Open in surfer and save as:

Open example.grd in Surfer (as a grid: file-> open). Then save it, for example with the name example_saved_by_surfer.grd. Remember to chose “GS ASCII (*.grd)”.

Load the saved file in Matlab

[matrix xmin xmax ymin ymax]=grd_read('example_saved_by_surfer.grd');

---Coded by Alberto Avila Armella, updated and improved by Jose Maria Garcia-Valdecasas

• MATLAB release: MATLAB 7.4 (R2007a)

[Sarah Reed]

Hi, this may be just be due to my beginner's level in Matlab, but I keep getting the "Undefined function or variable" error for the surfer grid I want to import. I called the function with the name of the Surfer grid ascii file, with and without the extension. The grid file is in the current directory with the function. Do I need to do something to set the path? Thanks for any thoughts you could offer.

[Frederic DONDIN]

Very helpfull

[Gabriel Ruiz]

Cool, man!!! I just tested this new version of grd_read and... it's very nice!!! The improvement really works.

[Mel]

Following Sarah Reed's post.
Make sure that you create a string file called "namefile" to run the grd_read_v2 function.
This may be done using "strcat" if the file name contains numbers and letters. e.g.
namefile=strcat('dem',num2str(1999),'.grd');
then run the function
>> [matrix xmin xmax ymin ymax]=grd_read_v2(namefile);

Hope this helps anyone in the future who uses this code (I encountered the same error as Sarah initially too).

[Josh]

Awesome! Now that you can create the .grd file from Matlab, it would be great if you could also use Matlab to open surfer, using something like:

!C:\Program Files (x86)\Golden Software\Surfer 9\surfer.exe

(though hopefully more elegant) and then load the file as well. I am creating a Matlab GUI, and would love to be able to invoke and graph matlab data through Surfer.

[XIAOMING]