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Creating a model to calculate apparent dips for geological cross section line

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10-13-2023 02:27 PM
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Masaryk
New Contributor

Hello, 

 

I am trying to make a tool in the model builder for use in constructing geological cross sections. The relevant data for this tool includes: 

Plana Fabric data:

Relevant attributes are lat/long, STRIKE (orientation of a plane; azimuth), and DIP (angle which the plane is tilted to the right of the STRIKE bearing). 

 

Bedding data: same attributes as above

 

Cross-section line: I have added a "calculate geometry" field to display the bearing of the cross section line. 

 

 

Here is the goal in model builder: 

-Calculate bearing of cross-section line

-Create buffer around cross-section line

-Select data from the bedding and fabrics datasets within that buffer

 

I was able to get this far. What I would like to add to the process is: 

-Calculate apparent dip of the planes with respect to the bearing of the cross-section line

The problem is that I cannot reference the bearing from the XC line data table while doing a field calculation for the other data tables. This is important because the apparent dip calculation is as follows: 

Apparent Dip = arctan(tan(DIP)*sin(STRIKE-XCBEARING))

 

The problem is that the value for the bearing of the cross section is from the attribute table for the XC line, and the DIP and STRIKE data are from the tables for the plane data. How do I use joins/relates to be able to calculate this successfully? 

 

Next, I would like to add dip ticks to the cross section line (could be in a new layer). The apparent dips must be projected along strike of the data points to the cross section line. So I would want to add point data where a hypothetical line drawn along-strike the bedding/fabric data intersects with the cross-section line. Then, I can use a small line to symbolize the apparent dip angle at the cross-section line. So the azimuth of the dip-ticks in map view would be the bearing of the cross section line + the apparent dip. 

 

I can work out the trigonometric specifications to modify the equations such that these dip ticks go in the right direction at another point in time. For now, I want to know how to do what is described above. 

 

Screenshot 2023-10-13 at 4.22.01 PM.png

 

The point values containing apparent dips should all lie on the cross section line. I can stylize the points as a line with the anchor point on the cross-section line. I can make a new attribute which would add the bearing of the XC line to the apparent dip, so that the reference angle is the line instead of 0. Then, I can use vary symbol by attribute to display the dip on the cross section line. 

 

I know tools like this exist for ArcMap and the Python 2.7 products, but I can't find any for ArcGIS Pro. 

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