Lab 2: Data Quality Standards

 This week, we went through the process of determining road network data quality by comparing two road networks with a reference data set. The image below is a screenshot of the location of the 20 test points, the amount of points that computes to 95% confidence level. Test points were chosen at intersections for each of the data sets: USA Street Maps layer in pink and ABQ City Streets in blue.

After finding the matching intersections for each road network dataset, I used Ortho images to create a new reference point layer. Then, I created two new fields in the three new layers for X and Y coordinates. Using Calculate Geometry, I filled in the two fields with coordinates for all of the points measured in feet. 

I filled out the Horizontal Positional Accuracy Worksheet provided in the Positional Accuracy Handbook which uses describes the National Standard for Spatial Data Accuracy. The worksheet walks through calculations to ultimately find the NSSDA accuracy standard. I completed worksheets for the USA Street Maps test points and the ABQ City Street test points.

Here are the results for the accuracy assessment written in the formal statement standard of NSSDA guidelines:

Positional accuracy for USA Street Maps: Tested 36,695.47 feet horizontal accuracy at 95% confidence level

Positional accuracy for ABQ City Streets: Tested 7,742.1 feet horizontal accuracy at 95% confidence level