Module 2 - Standards

    This week, in the second Special Topics in Geographic Science lab, was about standards with concerns to data quality. 

    In this lab, we made an accuracy assessment of two road networks, one from Streetmap USA and the other from the City of Albuquerque. To start, we added our shapefiles to our map that you see below of both our road networks. With them, we then made a good few test points where the roads intersect, as you can see in the map, in order to preform our accuracy assessment. 

    Once done, we then added more detailed imagery to the map so that we could change 20 or so of our test points into actual reference points. When doing so, we placed these reference points where we believed was the exact center of the intersections. Once we had our 20 points, we then went back and placed our Streetmaps USA and City of Albuquerque points where they displayed the corresponding intersections in their shapefiles. With a total of 60 points between all 3 features, we then added xy coordinates to these points in order to formulate the accuracy statement you will see next. This was all done per the National Standard for Spatial Data Accuracy, where we subtracted out points from the road networks to then squaring and adding the x and y points together. After a few more calculations of getting the sum, average,  and root mean squared, we finally got our National Standard for Spatial Data Accuracy statistic. This is listed next for both of our road networks.

StreetMaps USA Data: Tested 374.33 feet horizontal accuracy at 95% confidence level. This data is less positional accuracy, making it less useful or reliable for accuracy calculations. 

City of Albuquerque Street Data: Tested 11.85 feet horizontal accuracy at 95% confidence level. With the level of accuracy given, this means that the data from the City of Albuquerque is usable with a high-level accuracy.

    Overall, this lab gave a good insight more into how one would use GIS with concerns to data accuracy. I hope as this course continues on that I can learn more and work more diligently through the work. 

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