How geosoft do horizontal derivative of a magnetic grid?

Hi @PankajKumarDas, You can use the Search tool on the Search Support page in My Geosoft to find info about each of the filters in MAGMAP. Since all of our application help is now online, the results will include all help files, Knowledge Base Articles, or lessons available relating to your search term.

So for example, here are the results when you search for Horizontal Derivative.

The second line is a help file (you can tell by the question mark symbol to the left). This one shows you the expression that is used to calculate the Horizontal Derivative.

I hope that helps!