In November 2014, the American Society for Photogrammetry and Remote Sensing (ASPRS) released an updated standard, Positional Accuracy Standards for Digital Geospatial Data, to tie together past experience with current industry practice of preparing data, but not plotting the resulting maps. The new standard provides guidelines for calculating both the vertical and the horizontal accuracy. Prior standards include the National Map Accuracy Standards (NMAS), which were developed in 1947, the 1990 ASPRS Accuracy Standards for Large-Scale Maps Standards and 2004 ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data. None of the previous standards was designed to address the current technologies available for LIDAR, orthoimagery or digital camera mapping. The 2014 ASPRS Standards, were therefore created to help address the new technology. The new standards focus on the higher levels of accuracy that are currently available using the latest technology.
A portion of the updated 2014 ASPRS Standards addresses vertical accuracy. Vertical accuracy focuses on accuracy in the z direction. There are several testing methods available for vertical accuracy and the method chosen depends upon the data terrain: non-vegetated terrain versus vegetated terrain. ASPRS introduced the updated classifications for accuracy types in the 2014 standards. What was once known as Fundamental Accuracy is now Non-Vegetated Vertical Accuracy (NVA) and Supplemental Accuracy is Vegetated Vertical Accuracy (VVA).
Read Complete Article: Vertical Accuracy Reporting in TerraScan