Special Topics- Data Quality Assessment- Module 3

 This week we were asked to assess the quality of two road network data sets, Street Centerlines and Tiger, by comparing the completeness of the data on a grid-by-grid basis. We then mapped the resulting data onto a choropleth map.

To run this assessment, I split the data so that each grid could be analyzed separately.  I then used spatial join and summary statistics tools to further process the data. I exported my statistics to Excel to more easily analyze it and found that the Street Centerlines had no data for one of my grids. In total the Street Centerline data was 10,671.1 km in length with 134 of the grids being more complete than the Tiger data. The Tiger data was 11,253.4 km in length with 163 grids being more complete than the Street Centerline data. The Street Centerline data had 5.4% less road coverage than the Tiger data.

After assessing the data in Excel, I returned to ArcGIS and created a field to calculate the percentage difference between the datasets. There was an median of -0.18% difference in coverage between the Street Centerline and Tiger data.

I used this percentage difference field to create my choropleth map: