topic Re: comparing two rasters in Spatial Data Science Questions

comparing two rasters

RaySirois — Fri, 12 May 2017 00:39:02 GMT

I have two raster files that I want to compare spatially. One file was created using kernel spatial analysis of all points in a specific area and the other had the same analysis but of points where an event occurred. I am trying to look to see if population density plays a role and to spot the specific areas that do. Can anyone suggest the best way to analyze this data to get that type of result

Re: comparing two rasters

DanPatterson_Retired — Fri, 12 May 2017 00:43:58 GMT

an image of the files would help. Can it be assumes they are for the same extent and cell size? There are many ways to 'compare' results, beginning with simple subtraction, but that would be too easy

Re: comparing two rasters

RaySirois — Fri, 12 May 2017 00:58:48 GMT

the images were created using kernel density analysis. the are of the same extent.

Re: comparing two rasters

RaySirois — Fri, 12 May 2017 01:01:18 GMT

I am new to raster spatial analysis and any help or guidance you could provide in this area would be greatly appreciated. I tried the subtraction and I felt like it wasn't showing what I wanted to see. what other tools would you suggest

Re: comparing two rasters

DanPatterson_Retired — Fri, 12 May 2017 01:46:59 GMT

by images... I meant a screengrab .... sorry

Re: comparing two rasters

curtvprice — Sat, 13 May 2017 00:14:15 GMT

Minus displays the difference between two rasters cell by cell -- so I would start with that, and visually compare that with pop density using the swipe tool. Is there something wrong with your Minus result?

The Raster Calculator tool allows you get fancier, for example to get percent differences you can try:

100 * (raster2 - raster1) / raster1‍