Calculate Equal-Area Slope of Longest Water Course

[Anonymous User]

Original User: Playa

I need some assistance in getting started in developing a python script to determine the Equal-Area Slope for the Longest Water Course of a catchment. The Longest Water Course is represented as a 3D Polyline.  I need to determine the Equal-Area Slope of the each 3D polyline within a feature class.

The formula to derive the Equal-Area Slope is attached below as two jpegs. I'm battling to figure out how to extract the necessary information from each polyline and store it in either python lists or python dictionaries that I can then use within the formulas to determine the Equal-Area slope and then add the result back into the Longest Water Course feature class within a new field.

Any assistance in getting the following going will be appreciated.

Regards

[Anonymous User]

Original User: aimong

Are you needing help with getting the values to put in your equations or do you have the values and need help creating the dictionaries and calculating your new field? If you need help getting the values from the 3D polyline perhaps you could create a list of what values you need. You could also post on the 3D analyst board.

[PeterWilson]

Hi Amy

Thanks for getting back to me. The Longest Water Course polyline is 3D. I'm struggling to figure out how to extract the values required for the formula out of the dictionary. For example:

Area = [(0+1)/2] x500 + ....

The 0 is the first vertex Z value assigned as the difference in height to itself, the 1 is the second vertex Z values difference in height from the first vertex Z value, the 500 is the length in meters between the the first and second vertex and so forth until all the vertices are accounted for.

Regards

[Anonymous User]

Original User: aimong

It sounds like you would need to add points along the line at specified intervals (distance between points) and have each point associated with a Z value (could be obtained from a raster)?