Abstract

Space, Time, and Datum Forensics: Aligning GIS Data on a Dynamic Earth
Track: Surveying
Authors: Michael Dennis

What is the datum of your data? Where? When? At what accuracy? Aligning data is essential in GIS but has become more challenging because positional precision is increasing and everything is moving. On our dynamic Earth, the difference between datums can change by a meter per decade. An example is the relationship between WGS84 and NAD83; both have many versions and change with time. This presentation shows what to look for, questions to ask, how to fix problems, and the cost of bad assumptions.