topic Problem with the output from Line Density Tool in ArcGIS Spatial Analyst Questions

Problem with the output from Line Density Tool

OleKoppert — Tue, 20 Feb 2024 08:44:46 GMT

Hello! I am working on my master thesis and want to analyze the density of the bicycle network of a relatively big town in Germany (ca. 380.000 people). I use data from OSM that I extracted with Overpass Turbo. The angular unit of the file was automatically in degree because of the GCS so I converted everything to a suitable PCS with meters.

Now the problem: I tested a lot with the line density tool to create an index like the papers my work is based on did. I chose an output cell size of 100 (to get 100x100m) and a search radius of 250 (that is based on the papers). As Area units I picked square map units and also chose the correct Output Coordinate System in the Environments part of the tool.

The results that I get from that are confusing to me. They range from 0,001 to 0,024. In my understanding that should be meters/squaremeters which is obviously way too low for a dense urban area. I tested a lot of different things but I just don't get what is going wrong here.

The mentioned papers say they used Math tools to make the values easier to interpretate but I don't know what they mean by that. Meters/Squaremeters should be the output and that is perfectly interpretable.

I hope someone can save me here, because I am really lost.. Thank you very much in advance!

Kind regards,

Ole

Re: Problem with the output from Line Density Tool

DanPatterson — Tue, 20 Feb 2024 10:43:17 GMT

Did you read the following to help you interpret your results

How Line Density works—ArcGIS Pro | Documentation

Also, if your data were initially in decimal degrees, you need to produce a new raster in a suitable projected coordinate system

Project Raster (Data Management)—ArcGIS Pro | Documentation

preferably one in the equal area or conformal projection classes (eg UTM )

Re: Problem with the output from Line Density Tool

OleKoppert — Tue, 20 Feb 2024 11:05:40 GMT

Thanks for your response!

Yes I did read how the line densitiy tool works. Also the tool automatically transforms the Feature Class to a Raster doesn't it? That is why I picked the suitable PCS (UTM 32) in the Line Density Tool. I just tried to convert it with the tool you mentioned and it changed nothing. I think because the Line Density Tool already did that.

I think the problem is either that I just don't understand the results (because I think 0,024 Meters per m² is very low) or that that my data is not in the correct format. But as I said I just pulled my data into ArcGIS, transformed it with the "Project" Tool to UTM32 so that the units are in meter and then I performed the Line Density Tool, which should be the right way shouldn't it? I should maybe mention that the visualization of density is perfectly fine, so it seems to work but I cannot work with that when I don't have values to interpretate.