GIS4930 - Module 1.2 - Data Quality Standards

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For this module, we were tasked with learning how to apply the National Standard for Spatial Data Accuracy (NSSDA) to find positional accuracy between two datatsets. We compared the City of Albuquerque street dataset with the StreetMap USA dataset, using orthophoto imagery as reference for accuracy.

To start we had to make the study area easier to analyze so I divided the study area into four quadrants so the test points would be evenly distributed across the region. At least 20 points of intersections, 5 being in each quadrant, and making sure that the points were at least 10% of the study area’s diagonal apart. For each point, I created three versions, one digitized on the orthophoto, one snapped to the City street dataset, and one snapped to the StreetMap USA dataset.

 

After assigning IDs and adding XY coordinates using, I exported the tables into Excel to calculate the NSSDA accuracy at the 95% confidence level. 

City of Albuquerque dataset:  

    Tested 13.18 meters horizontal accuracy at the 95% confidence level.  

StreetMap USA dataset:  

    Tested 151.56 meters horizontal accuracy at the 95% confidence level.

 

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