GIS Portfolio - Michael Malone

 This module focused on exploring triangular irregular networks (TINs) and digital elevation models (DEMs). The project culminated to creating a TIN and a DEM from the same set of points and then comparing the contours created from each. While I see the value and versatility of the using a TIN to quickly symbolize many different aspects of the data quickly, I believe the contours created from the DEM (red) are more accurate than those created using the TIN (black). The TIN contours are restricted to the surfaces of the TIN hence in the final product they appear jagged which lowers their overall accuracy.

 

  The task for this module was to perform an accuracy assessment on two versions of the same road network in Albuquerque. One was mapped by the city of Albuquerque (yellow) and one by Street Map USA (red). In order to perform the accuracy assessment twenty points per network needed created at matching intersections on each network. Then a reference point was digitized based on satellite imagery to represent the "actual" location for each intersection. XY coordinates were assigned to all sixty of the created points and the values were exported to an excel spreadsheet. From there the RMSE for each of the networks were calculated using the reference points. With this the accuracy assessment was completed resulting in the following: ABQ_Streets Positional Accuracy: Tested 14.84 feet horizontal accuracy at 95% confidence level. StreetMapUSA Positional Accuracy: Tested 158.56 feet horizontal accuracy at 95% confidence level.