The goal of this week's lab was to determine the completeness of two separate road networks for Jackson County, OR. One of the networks was the TIGER file which is created by the US Census Bureau, and the other was created by the county's GIS team. The methodology for determining completeness was based off of the method used by Haklay (2010) where the study area was broken into grid squares of equal area and the total length in difference between the two networks was compared. The network with longer road distance in each particular grid square was considered to be more complete. This was mapped by using the percent difference which was calculated by (total length of Jackson County-created network - total length of TIGER network)/(total length of Jackson County-created network) * 100.
When looking at the county as a whole, the TIGER network is more complete as it has a little more than 500 km of road than the network made by the Jackson county team. However, as shown in the map below, this does not mean that the TIGER network is more complete in all areas. The Jackson County team network was more complete for 45.27% of the grid squares, and the TIGER network more complete for 54.73% of the grid squares.
 |
| A comparison of completeness between the two road networks. The pink areas are where the TIGER network is more complete, and the green squares are where the Jackson County-created network is more complete. |
Haklay, M. (2010). How Good is Volunteered Geographical Information? A Comparative Study of OpenStreetMap and Ordnance Survey Datasets. Environment and Planning B: Planning and Design, 37, 682-703. doi:10.1068/b35097
No comments:
Post a Comment