How can I calculate the volume or area between contours in Surfer?

1. Click Grids| Calculate | Volume.
2. In the Grid Volume dialog, click Browse.
3. In the Open Grid dialog, select your grid file and click Open.
4. Set the grid file as the Upper Surface| Grid File and the Z level of the first contour as the Lower Surface (Constant Z = ).
5. Click OK.
6. Record the Volumes | Cut & Fill Volumes | Positive Volume [Cut] value or Areas | Planar Areas | Positive Planar Area [cut] value for areas from the report.
7. Repeat steps 1 - 6, generating a second report with the same grid file as the Upper Surface and the Z level of the second contour as the Lower Surface.
8. Subtract the second value from the first value to get the volume or area between the two contours.

Using Automation

• The contarea.bas script calculates the area between evenly spaced contour levels automatically. Download the script, open the BAS file in Scripter (comes with Surfer), and go to Script | Run. Follow the prompts to generate the report.

Updated October 31, 2017.