If you've converted a very large image into a grid file with the same number of grid nodes as the image had pixels, it's likely your resulting image map will look lower-resolution than the original image. This is because the default maximum image size for an image map is 3000x3000. You can easily adjust this though in the Surfer set file.
- Close Surfer.
- Open a Windows File Explorer window.
- Navigate to C:\Users\<your username>\AppData\Roaming\Golden Software\Surfer 15.
- Right click on the surfer.set file, click Open with, choose Notepad, and click OK.
- Scroll all the way down to the bottom of the file.
- In the $Hdr(Miscellaneous) section, the 13th entry down is MaxImageMapRes. After the equal sign, type the bigger of the two pixel dimensions of your image (so if it was 20000x15000, type 20000).
- Click File | Save to save the file.
- Open Surfer and create your image map. Now the image should be the appropriate resolution.
Updated September 19, 2017