Computing the Intersections of Planes

RockWorks | Utilities | Planes | Beta Intersections

This program reads a listing of planar orientations from the RockWorks data sheet and calculates the lineations resulting from the intersections of all of the planes in the file. The linear values will be stored in an ASCII text file that can be displayed in the RockWorks text editor when completed.

The number of intersections that will be computed is:

number = n ( n - 1 ) / 2 where n is the number of individual planes in the input file.

As the number of original planes increases, the number of resulting lineations increases dramatically. For example, a data set with 20 planes will result in 190 lineations, and 200 planes will produce 19,900 lineations!

How does this differ from the Beta Pairs tool? Beta Intersections reads a listing of individual planar bearing and dip measurements from the data sheet and calculates the lineations that result from the intersection of each plane with each other plane in the data set. This can result in a tremendous number of computed lineations! Beta Pairs, on the other hand, reads strike and dip measurements for pairs of planes, and for each pair computes the single resulting lineation.

Menu Options
Step-by-Step Summary

Menu Options

• Input Columns: The prompts along the left side of the window tell RockWorks which columns in the input datasheet contain what data.
  Click on an existing name to select a different name from the drop-down list.
  • Direction: Select the name of the column that contains the bearing measurements (either strike bearing or dip direction, which you'll specify below).
  • Dip: Select the name of the column that contains the dip angle measurements. Note: Horizontal is considered to be zero, and dipping straight down is entered as 90.  Negative dip angles are not supported.
• Input Format: In the pane to the right, select the format in which your source data is listed by clicking in the appropriate radio button.
  • Right Hand Rule:  Choose this if your planar data are entered as strike bearing and dip angle, with the dip direction being 90 degrees clockwise from the strike azimuth bearing.
  • Dip Direction:  Choose this if your measurements represent dip direction and dip angle.
• Output File: Click on this item to type in the name to assign to the ASCII text file to be created, which will list the bearing and dip angle of the intersection lineations. Typically, this file name should have the extension "TXT."
• View Output File: Insert a check in this box if you want the program to display the output file in the Windows Notepad text editor upon completion.
  
  

Step-by-Step Summary

1. Access the Utilities program tab.
2. Create a new datasheet and enter/import your strike and dip data (or dip direction, dip angle data) into the datasheet.
   Or, open one of the sample files and replace that data with your own. (In the Samples folder, an example file = "\RockWorks17 Data\ Samples\Strike_and_Dip_Map_01.rwDat".)
3. Choose the Utilities | Planes | Beta Intersections menu command.
4. Enter the requested menu options, above.
5. Click the Process button when you are ready to continue.

The program will read the planar orientation data from the data sheet and write each intersection lineation into the specified file on disk. The output file will be displayed in the Windows Notepad if you have requested this. 

See also: Computing the Intersection between Pairs of Planes

  Back to Planes Menu Summary

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