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Extract Slope Values from Terrain:Slope Degrees in AGOL

Question asked by Diomedes275 on Apr 19, 2017

I need to calculate slope in percent gradient for points in a given feature class.  My workflow is as follows:  

1. Set up an .mxd with the desired feature class in a projected coordinate system and the the data frame in the same projected coordinate system (NAD83 UTM z10)

2. Import Terrrain: Slope degrees layer from AGOL, and project that on the fly.

3. Use the "Extract Values to Points" tool in Spatial analyst tools.  

4. A new feature class is created with a field called RASTERVALU.  Now here is where my questions begin.  Is this value the slope in degrees?

5. Create a new field called "PCNT_SLP" and make it a double field type.

6. Populate the field with a calculation that converts degrees (RASTERVALU) to radians, calculate the tangents of the radians and then multiply by 100.  The python formula I put together for the field calculator is:

math.tan( math.radians( !RASTERVALU! ) ) *100 

 

Am I going about this correctly or am I way off?

 

thanks,

John

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