Ask A Cartographer

tract-level commuter flow map

April 18 2009 | 0 comments
Categories: ArcGIS Methods, Map Data

I would like to make a map like the one on page 2 of this .pdf:

This example is at the county level, but mine is to be at the tract level. I already have a large matrix that contains commuter counts between each tract in my study area (origin tracts down first column; destination tracts across first row).

Also, the tract geocode format I'm using is single-cell, as follows: 06007000101. I expect I'll be importing this info into ArcMap. Is this the proper format?

Mapping Center Answer:

What you want is often called a "Spider Diagram".  There is an ArcScripts sample called "Spider Diagram Tools for ArcGIS 9.2 (New and Improved)" that should help you.  The only caveat may be what it takes to get your data into the model that this script supports.  Given your tract-level data, transforming your data is by far a better way to go versus digitizing lots of "spider legs".  I gues that also answers your last question, which is yes, though ArcMap may already read the data.

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |