When is the best time to implement a better model?

 

Earl F. Burkholder, PS, PE

Global COGO, Inc.

Las Cruces, New Mexico 88003

globalcogo@zianet.com

January 24, 2004

 

I recently received two very important pieces of mail – the January 2004 issue of PE&RS, the Journal of the American Society of Photogrammetry and Remote Sensing and the January 2004 issue of Geospatial Solutions.  The PE&RS journal contains a 50-page authoritative 10-Year Industry Forecast for the remote sensing and geospatial information industry in the United States while Geospatial Solutions addresses geospatial legislation, market outlook, and business models.  Each publication estimates the spatial data segment of the US economy to be measured in billions of dollars annually and anticipates continued growth.  Looking ahead, authors in each publication note the importance of avoiding duplication of effort, development of appropriate standards, and establishing functional interoperability for all spatial data users.  The rate of progress is mind-boggling.  However, I fear progress is moving too quickly if policy and standards for generating and using digital spatial data are established on the basis of an obsolete geospatial data model.

 

At some point in the future, spatial data will be referenced to a 3-D model that has a single origin and competently supports the goals listed above.  Current progress is impressive, but future progress will ultimately be hampered by continued use of the 2-D plus 1-D model that uses separate origins (datums) for horizontal and vertical data.  A comprehensive 3-D global spatial data model (GSDM) has been defined that readily accommodates digital spatial data, fully supports existing 2-D/1-D uses, utilizes the same set of equations world-wide (no projection zones or constants), provides a concise definition for spatial data accuracy, and offers simple standard procedures for handling spatial data.  The GSDM is described in the article, “The Digital Revolution Begets the Global Spatial Data Model (GSDM)” published by the American Geophysical Union in the 15 April 2003 issue of EOS, Transactions.  Other articles on the GSDM are posted at www.zianet.com/globalcogo/refbyefb.html.

 

The GSDM contains little or no new science.  The solid geometry equations are all public domain and published in various sources in addition to those given above.  The “new” characteristics of the GSDM are a consequence of beginning with an assumption of a single origin for spatial data and building a 3-D database using geometrical components attached to the rectangular earth-centered earth-fixed (ECEF) reference frame as defined by the US Department of Defense.

 

When is the best time to begin using a 3-D model?  The decision may be analogous to that CEO contemplating construction of a $100 million vacuum tube plant in 1955.  The transistor had already been invented but the vacuum tube market had not yet collapsed.  Hindsight being what it is, the $100 million would have been better invested in building a transistor plant.  In the spatial data case, the benefits of using the GSDM will continue to grow and each user will make the transition when it is in his or her self-interest to do so.  “When?” is still the unanswered question.