topic Re: 3D Analyst - Add Surface Information generating slope values of 9999 and 10000 for all segments in 3D Questions

3D Analyst - Add Surface Information generating slope values of 9999 and 10000 for all segments

JWest1 — Wed, 03 May 2023 16:48:06 GMT

I am using Pro 2.9.5 and 3d Analyst trying to add some z-values to some polylines. I have a DEM I am using as the surface and so the only option I have for processing is Bilinear.

I run the tool with the following parameters:

Input Features: Polylines
Input Surface: DEM
Output Property: All selected
Method: Bilinear
Sampling Distance: <Null>
Z Factor: 1
Noise Filtering: <Null>

When the process completes the z values are added to the features but the slope values come in as Min Slope: 9999, Max Slope: 10000, Average Slope: 10000 for nearly all of the features. I have tried troubleshooting by creating a TIN as well as reviewing the raster cell values to ensure that there is good data there.

I have even created a new feature class and am getting the same issue.

Edit: I had the Sampling Distance here as 0 but there is no value in the tool when I run it.

Re: 3D Analyst - Add Surface Information generating slope values of 9999 and 10000 for all segments

DanPatterson — Wed, 03 May 2023 13:25:19 GMT

Add Surface Information (3D Analyst)—ArcGIS Pro | Documentation

it has your sampling distance as 0 which doesn't seem correct if you are using a raster

sample_distance
(Optional)
The spacing at which z-values will be interpolated. By default, the raster cell size is used when the input surface is a raster, and the natural densification of the triangulated surface is used when the input is a terrain or TIN dataset

Re: 3D Analyst - Add Surface Information generating slope values of 9999 and 10000 for all segments

JWest1 — Wed, 03 May 2023 13:27:52 GMT

Sorry, I just edited my original post. There is no sampling distance in the tool when I run it.

Re: 3D Analyst - Add Surface Information generating slope values of 9999 and 10000 for all segments

JWest1 — Mon, 08 May 2023 18:37:01 GMT

So, I think I have isolated the issue but am having a hard time identifying a way to correct it. The SHAPE_Length of the polyline is in DD and is showing the lengths in the hundred thousandths of a unit and then the Z coordinates are calculating in meters so the slope values are generating with incredibly large numbers or even sheer cliffs as indicated by the 9999 and 10000 values.

Yep, fixed it and corrected the issue. Turns out there was a projection issue with the WGS failing to convert the DD measure to run the math for the slope calculation driving numbers to exceed possible slope values.

Thanks for all the help!