2 replies to this topic

[WholeMilk]

Hi,

I am doing a research project and am looking for any source of data that provides total highway road mileage by census tract. Do you think the data is available somewhere out there? (Specifically, for the state of Virginia)

Or do you think I'll have to do some database management and start clip some aggregated highway road shapefile? I know FHWA has some good data to start with..

Thank you very much!

[David Medeiros]

Your'e not likely to find this as a complete data set anywhere. But it's a fairly easy operation in a GIS. First intersect the road layer with the tract layer then summarize the resulting table of attributes on the mileage attribute (may have to create new field first).

[Mapgeek]

Hi,

I am doing a research project and am looking for any source of data that provides total highway road mileage by census tract. Do you think the data is available somewhere out there? (Specifically, for the state of Virginia)

Or do you think I'll have to do some database management and start clip some aggregated highway road shapefile? I know FHWA has some good data to start with..

Thank you very much!

You are going to have a very difficult time with this one. One of the landmarks that can be used to delineate a Census Block (and in so doing a Census Tract) is roads. This means that one road can potentially be in 2 different Census Tracts. You then have to figure out how you are going to handle that. Are you going to put half the road in one Tract or are you going to have the full length of the road in each Census Tract which doubles the length of the roads that are being used as a boundary?

I'm not sure what kind of analysis that you are doing, but when I did a study that was trying to figure out road density over a specific area, I ended up doing a fishnet grid to get around any issues with roads being used as a boundary between two measurement units.
Good luck.