When is the best time to implement a better model?
Global
COGO, Inc.
Las
Cruces, New Mexico 88003
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.