topic Re: kernel density by square miles in ArcGIS Spatial Analyst Questions

kernel density by square miles

Anonymous User — Tue, 06 Mar 2012 14:19:26 GMT

Original User: Jim_satx

Ran a kernel density on mass points (65000). I seem to have forgotten how to obtain density per square mile values from the raster. My data frame properties are correct (map units feet, etc.) I am currently getting values in the millions when the highest density should be <400 per square mile. Thanks;

Re: kernel density by square miles

Anonymous User — Tue, 06 Mar 2012 15:14:57 GMT

Original User: Gaya6337

Hi,

Make sure the raster is projected before using the Kernel density tool. If your data is stored in a geographic coordinate system, for example GCS_NAD_1983, where the base units are decimal degrees, the results of a density will not be easy to use since they will be expressed in degrees, not a unit like feet, meters or miles. Reprojection of the data would be advisable if your information is in decimal degrees.

-Gayu

Re: kernel density by square miles

Anonymous User — Tue, 06 Mar 2012 15:32:36 GMT

Original User: Jim_satx

Thank you very much, that was the problem.

Hi,

Make sure the raster is projected before using the Kernel density tool. If your data is stored in a geographic coordinate system, for example GCS_NAD_1983, where the base units are decimal degrees, the results of a density will not be easy to use since they will be expressed in degrees, not a unit like feet, meters or miles. Reprojection of the data would be advisable if your information is in decimal degrees.

-Gayu

Re: kernel density by square miles

JaredRutledge — Tue, 20 May 2014 13:15:11 GMT

Greetings Everyone,

I am sorry for this question, but I am having difficulty performing the reprojection on the fly. My point data are in GCS_WGS_1984.

I go to the kernel density tool, then I select environments.

From Environments I select output coordinates, from Output Coordinates System I select As Specified Below.

This is where I run into a road block can anyone assist me with a step by step guide on how to get these geographic coordinates into something I can use with the kernel density tool?

Thanks,

J

Re: kernel density by square miles

Anonymous User — Tue, 20 May 2014 18:50:38 GMT

Original User: curtvprice

This is where I run into a road block can anyone assist me with a step by step guide on how to get these geographic coordinates into something I can use with the kernel density tool?

The key is to use the Project tool to project the points into the same output coordinate system as your raster, or at least a projected (not lat-long) coordinate system.

See the response on this [post=390150]other thread.[/post]