Special Topics- Data Quality- Standards- Module 2

 This week we used the standards set by the National Standard for Spatial Data Accuracy (NSSDA) to determine positional accuracy of a provided road network. The positional accuracy of the test data was compared to an established data set as well as to reference points obtained to orthographic images of the study area.

To determine accuracy we chose a sampling of 20 points meeting specific criteria (no less than 4 per quadrant, greater than 10% of the diameter in distance from other points) along intersections. We established reference and testing feature classes for each intersection. 

After creating our feature classes we added XY coordinates to the data. We used excel to calculate the RMSE and NSSDA values.

Based on my results I determined the following about the positional accuracy of each data set:

The ABQ street data tested  4.18 feet horizontal accuracy at 95% confidence level.

The Street Maps USA data tested 434.85 feet horizontal accuracy at 95% confidence level.