Issues using Kernel Density

Question

Hi

I'm trying to use Kernel Density to develop a 2-D field showing distance decay around a circle. I have converted the polygon circle to a line for input into the KD tool.

Eventually, I want to specify an intensity at the edge of the circle and have the field created by this tool show the decay of this intensity out to the specified Search Radius. Not clear yet how I will specify this maximum intensity at the circle edge - I was thinking of using Population and setting this to Shape_Length (i.e. the circumference of the circle).

My initial attempt is resulting in this error:

Kernel Density
=====================
Parameters

Input point or polyline features KERN_01_FeatureToLine
Population field Shape_Length
Output raster C:\M1S\220722 (KERN)\K_01
Output cell size 0.2
Search radius 200
Area units SQUARE_METERS
Output cell values DENSITIES
Method PLANAR
Input barrier features
=====================
Messages

Start Time: Friday, 22 July 2022 9:59:10 AM
ERROR 160180: The junction has invalid geometry (i.e., non-point or invalid location).
Failed to execute (KernelDensity).
Failed at Friday, 22 July 2022 9:59:13 AM (Elapsed Time: 3.16 seconds)

Please also see screenshot attached of parameters entered.

Can you please advise:

1. how I can correct this invalid geometry issue

2. I would appreciate any pointers regarding my proposed use of this tool. From what I can tell, this is not the conventional application of Kernel Density

KERN query.jpg

danretired · Answer

I think the problem is that you appear to have one point, or if that is you point densified representation of a circle, then the extent is going to be exceptionally small (less than cell size?)

MorrisR2 · Answer

Hi @DanPatterson

Appreciate your patience. Went back to basics, opened a new file, set the Projected Coord System to NZGD 2000 New Zealand Transverse Mercator, added a point, ran KD and got the same result.

The Documentation says ' If you are not sure what to use, set the Output Extent in the Environment setting to Default.' Which is what I had it set to, as well as trying with a few other variables (pls refer attached). Anything else you can think of which could be tripping me up?

Cheers

Richard

KERN query3.jpg

danretired · Answer

010092: Invalid output extent.—ArcGIS Pro | Documentation

and there are tons of similar mentions of this in the Community.

A good idea is to ensure that you explicitly set your parameters for the tools and the environments.  For kernel density, use projected data and a good practice is not to mix data in different coordinate systems in a map for anything other than having a quick look.

If you are still having issues, open a new map, add just that one input layer, then run the tool