Open GIS
Consortium, Inc. (OGC) announced that the OpenGIS Grid Coverages
Implementation Specification, which reached general consensus in OGC
last year, has been finalized and released to the public. It is
available at http://www.opengis.org/techno/specs.htm.
The term “Grid Coverages” refers to satellite images, digital
aerial photos, digital elevation data, and other phenomena represented
by values at each post in a “raster” coordinate system (as opposed to
“vector” geodata, in which digital map information is represented
using polygons and lines). The specification describes an open
interface that provides communication between software systems for
purposes of requesting, viewing, and performing certain kinds of grid
coverage analysis such as histogram calculation, image covariance and
other statistical measurements. Interoperability for a wider range of
image operations awaits the OpenGIS Image Exploitation Services
Specification, which is in progress in OGC’s Technical Committee.
Yonsook Enloe, an OGC contributor and employee of SGT working in
NASA’s Earth Science Enterprise (ESE) projects, is Coordinator for a
CEOS task team creating prototypes that implement OpenGIS interfaces
in support of land cover management. She states: “This specification
will accelerate the extraction of valuable earth information from
earth observation satellites and provide for more rapid studies of
important earth dynamics such as temperature distributions,
agriculture, forestry, forest fire management and global trends.”
The OpenGIS Grid Coverages Implementation Specification sets forth
an extensible framework supporting the industry’s progress toward
interoperable geographic image processing and analysis. It has been a
major catalyst for increasing cooperation between all the major
standards groups working in the area of earth imagery. Experts in
ISO’s Technical Committee 211 and JTC1’s Subcommittee 24, the
Committee on Earth Observation Satellites (CEOS) EOGEO initiative, the
GeoTIFF effort, and others have all worked with OGC to bring the
various groups work into alignment.
The OpenGIS Grid Coverages Implementation Specification was
written with COM and CORBA implementations in mind, but is general
enough in nature to be extended to include other Distributed Computing
Platforms (DCPs) such as JAVA. Most implementations will involve
client/server processing over the web. The specification allows for
efficient access to very large datasets, and supports N dimensions
even though most implementations of the specification will be 2D. The
specification also supports: GeoTIFF, an industry standard geographic
image format; a wide range of grid data from raw to thematically
classified grid coverages; a number of color models; variable value
sequencing and pixel ordering; and all grid geometries and spatial
referencing systems consistent with geometries and spatial referencing
in the OpenGIS Simple Features Specification.
The following companies submitted this implementation
specification, in response to the an OGC Request For Proposals:
– Cadcorp Ltd
– ESRI
– Intergraph Corporation
– Laser-Scan, Ltd.
– Oracle
– PCI Geomatics, Inc
OGC, an international consortium of more than 200 corporations,
agencies and universities, coordinates collaborative development of
the OpenGIS Specification and collaborative business development to
support full integration of geospatial data and geoprocessing
resources into mainstream computing. Visit the OGC website at
http://www.opengis.org.
Contact:
Open GIS Consortium, Inc.
Mark E. Reichardt
(301) 840-1361 Voice
