Lab 5 - Spatial Accessibility

This week in Applications in GIS was a bit of a chore because it included quite a bit of Excel and I'll just say, maybe it was a good thing I had this refresher now instead of later. For Lab 5 we did a few exercises in the ArcGIS Help Tutorial to learn how to build network datasets. That Help guide is a lifesaver each and every time I get into ArcMap now so the tutorial lessons were a nice change of pace for this class. I am challenged every week but this week I already knew where to look in the Help directory because the page was already open and I just had to re-read the section again.

After working through the tutorial exercises we did a little work with spatial access based on proximity and this is where Excel came out to play. The lab required us to identify which areas (counties and then smaller census tracts) had access to hospitals based on the data we were given. After doing some quick work with Spatial Joins to determine distances between points and applying a nice graduated color scheme we started with the Cumulative Distribution Functions. I think I spent half of my time on this lab figuring these things out (because they came up again at the end of the lab). By exporting opening the .dbf file for a layer in Excel you can create a normal .xlsx spreadsheet and manipulate the data without messing with the actual map layer. Eventually I figured out how to sort the data efficiently, add the formulas i wanted, and sort the data again without messing up the formulas I entered earlier. In the end I had a couple of nice looking scatter plots that showed exactly what I was trying to show. Don't let me fool you, I skipped ahead and came back o finish this at the end.

Then came the spatial accessibility analysis with a network dataset. We looked at the effects a potential community college campus closure would have on student commutes and access. The graphic below is the result of Service Area Analysis using the Network Analyst Tool in ArcGIS with limits for a 5, 10, and 15 minute drive.