Measuring the strike and dip of a geologic structure can be quite useful in determining its physical and mechanical properties, such as faults, folds, joints, and other internal weaknesses. You can use Surfer 10 to display your strike and dip values acquired from your field calculations on your map. Follow along as I demonstrate by using the Conifer.grd found in the Surfer 10 Samples folder and a set of sample field data that you can download by clicking on this Conifer.txt link.
Display the strike and dip information on a map
- First open the Conifer.txt file in the Surfer worksheet. It should look like this: Use Data | Transform to transform your strike direction (azimuth) data with the following formula: F=(E+90)*-1. Save and close the file. The transform is required so that the strike/dip symbol is oriented correctly.
- Go to Map | New | Contour Map. Choose Conifer.grd from the Samples directory and click Open.
- Go to Map | Add | Post Layer, select the newly saved Conifer.txt file and click Open.
- In the General tab of the Property Manager, set X Coord = Column A, Y Coord = Column B and Angle = Column F (transformed strike direction). Set the Frequency to 100.
- Expand the Default Symbol section and Marker Properties subsection. Change the Symbol Set to GSI Geologic Symbols. Change the Symbol to a strike/dip symbol (i.e. Symbol 120 or 121).
- If you want to show the labels for the dip amount, go to the Labels tab and choose to show the labels for Column D (dip amount). You may need to adjust the label position relative to the symbol.
You now have a contour map of Conifer displaying strike and dip. If you do not have field data with strike and dip information but you have a grid file, you can use Surfer to calculate the strike and dip information and display it on your map. To calculate the strike and dip values of a grid file please see the Knowledge Base article, How can I find the strike and dip values for my grid file and display it on a map?