This week we discovered how complicated it can be to calculate completeness of road networks.  First to calculate completeness is a comparison to another source of data (so depends on how complete/correct that information is, more about this in a minute).  We read a few articles on methods and data sets of comparing road centerlines.  Then in lab we compared a data set from Jackson County, Oregon to the 2000 TIGER Road data.  Seo, 2009, reports 2000 TIGER data was so poor that it required an extensive overhaul to be able to better meet the needs of the 2010 Census (Seo, 2009).  Going into this lab with the knowledge of the 2000 TIGER data I had expectations that the County Centerline data would be far more complete.  The choropleth above shows 297 grid cells, of those 162 show Local info to have less road kilometers than Tiger data, 134 cells show the local data to have more kilometers and 1 cell had no road kilometers in either data set.  The cells in green show where more kilometer or roads were found in the TIGER data than in the local County.  The darker the color the higher the percentage of  difference.  This depiction does not question if more kilometers of roads is a good method of calculating more complete data. 


Reference:

Seo, S., & Ohara, C. G. (2009). Quality assessment of linear data. International Journal of Geographical Information Science, 23(12), 1503–1525. doi: 10.1080/13658810802231456