Based on our findings here we hope you will help us spread the word and promote change by
· Testing GPS data and stations in your own area
· Occupying truth
· Communicating those results with GIS/GPS community
· Educating users on these issues
Test GPS data and stations in your own area
Our step-by-step, detailed methods are to incourage you to conduct your own tests. The latest projection (.prj) and transformation (.gtf) files are already installed in ArcGIS 10.1. Melita Kennedy, ESRI has made these files available for users not yet in ArcGIS 10.1 but desiring this functionality. Likewise, this functionality is already installed in Pathfinder Office 5.3 but can be added to any version of PFO via this Pathfinder Office .csd file.
In my demonstrations, locations were compared relative to each other. I would be eager to see an updated OPUS 2011 position (today's standard) versus the same SSF with various processes. This would allow these workflows to be analyzed for both accuracy and precision.
Communicate your results with GIS/GPS users, dealers and software companies
Datum shifts vary highly. In tectonically active areas such as the Western US and AK, these datums shifts are significant. This article has not addressed the latest NAD83 epochs for the Pacific NAD83(PA11) or Marianas Plates NAD83(MA11) but if a ticket shows up in my mailbox, I’ll be more than happy to come and do some testing on the beach or even AK if during the salmon runs!
Educate users of these issues
In his paper “Do the Right Thing, M Dennis, NGS notes -
‘The software has also become easier to use, so that it is now possible for a user with minimal training to collect and process GPS data. Such “user-friendly” software has made GPS a much more accessible technology, yet this ease of use has come at a price: It is also easy for users with little geodetic knowledge to unwittingly generate erroneous coordinates.’