After making two surface map, isochron or thickness map have been done. This to know the thickness of sediments between the surface maps. Steps for making isochron map is as show below:

​

1. Firstly, right click on the “Seismic horizon 1” map at the Input section on the left and go to “Settings”.

2. Go to “Operations” tab, click on “Calculations” and select “Make thickness map”. Then fill in the “Base Surface” at the bottom. The map will appear.