2. SDTS Raster Profile with Basic Image Interchange Format (BIIF) Extension (SRPBE), SDTS Part 5

Intended Use --

SDTS Part 5 is designed for the transfer and archive of digital geospatial raster, grid, and image data. The primary SDTS objects are grids and grid cells. USGS is now using Part 5 for the distribution of DEM's. Future use of the SRPBE for USGS DOQ's and DRG's is also being considered. The BIIF extension supports image data and provides a connection with image standards used in the military and intelligence communities. Part 5 can also reference separate files which use standard compression methods.

Part 5 takes advantage of the capabilities of both SDTS and BIIF. SDTS has a geographic information focus and provides the capability of encoding raster grid and image data, georeferenced information, simple color look-up tables, data quality reports, data dictionary information, and other such metadata.

ISO/IEC 12087-5 Basic Image Interchange Format (BIIF) has an image transmission focus and provides an efficient image file format, image compression, image blocking or tiling, variety of color models, and visualization controls. The portion of BIIF that is common with SDTS Part 5 is also within the scope of the National Imagery Transmission Format / NATO Secondary Imagery Format (NITF/NSIF) profile to BIIF. The integration of SDTS and BIIF provides a foundation for interoperability in the interchange of raster and imagery data among applications.

Once Part 5 is approved by FGDC, DOD will begin planning the distribution of raster products (e.g., NITF-based products) using SRPBE.

Primary Sponsors, Interested Groups, and Contacts --

USGS will use Part 5 for raster and image data distribution, beginning with DEM data in 1997. The primary developers of Part 5 are the National Imagery and Mapping Agency (NIMA) and USGS. Other contributors include the Joint Interoperability Test Command (JITC), the BIIF editorship, Geomatics Canada, NOAA, and the Digital Geographic Information Exchange Standard (DIGEST) team under NATO. Representatives from these agencies formed the Raster Standards Convergence Working Group (RSCWG). The RSCWG, through the FGDC's Subcommittee for Base Cartographic Data (SBCD) has submitted SDTS Part 5 for FGDC approval in 1997 or early 1998..

Contact the SDTS task force at sdts@usgs.gov

Additional information is available on-line at the SDTS web site

http://mcmcweb.er.usgs.gov/sdts

Documents --

The SRPBE exists as a documented part (Part 5) of SDTS. A working draft is ated July 1997. A public-review version of the document should be available in September 1997 from the FGDC Standards Working Group site at

http://www.fgdc.gov/SWG/

or from the SDTS site at

http://mcmcweb.er.usgs.gov/sdts

An additional document that describes the product mapping to the Raster Profile from USGS DEM is also available at the SDTS web site.

The article "Developing a Raster Profile for the Spatial Data Transfer Standard" by Dave Greenlee is in the December 1992 issue of Cartography and Geographic Information Systems.

Software --

The Common Software Platform and the SDTS++ toolkit provide access tools that can be used for Part 5.

Translators --

Raster profile translators have been developed for ERDAS and MicroDEM.

Data --

Sample raster profile DEM data for Mt. St. Helens is available at the SDTS web site. The SDTS site also has sample multispectral image and thematic data from ERDAS. Nationwide DEM data is being mass converted to the SRPBE and will be available in 1998.

Conformance Testing --

Arrangements for conformance testing of Part 5 are not yet defined, but may be done through DOD facilities.

Future Plans --

The review period for the "proposal" for FGDC approval of SDTS Part 5 closed September 1, 1997

(http://www.fgdc.gov/SWG/sub4_1.html).

FGDC will now prepare for the review of the actual profile document as one of the next steps to gain FGDC approval. ANSI and ISO approval for SDTS Part 5, along with Parts 1, 2, 3, & 4 of SDTS, will also be sought. Development and approval of conformance testing tools and procedures is planned. Additional Part 5 translators are anticipated.

More data (USGS DEM's) in SRPBE will become available in 1998. Use of Part 5 for USGS DOQ's and DRG's is being considered. The Naval Research Laboratory and the National Ice Center have plans for an Arctic ice climatology CD using the Raster Profile of SDTS. NOAA is converting raster sea ice data from SIGRID format to SDTS. EarthWatch, Inc. is investigating SDTS and Part 5 as a possible output format for images from its EarlyBird satellite. Bechtel Nevada and DOE are also investigating Part 5 for airborne multispectral scanner data at the DOE Remote Sensing Laboratory.

There is a need to identify and explore common interests with the GeoTIFF effort (Ritter & Ruth, 1997). Developers of GeoTIFF indicate that there may not be new versions of GeoTIFF and there may be an effort to define an implementation relationship between GeoTIFF and SDTS, much like the SDTS relationship to BIIF. See also "Re: Relationship between GeoTIFF and SDTS" (1996) from Niles Ritter at

http://www.pci.on.ca/~warmerda/geotiff/msg00277.html

and the GeoTIFF page at

http://home.earthlink.net/~ritter/geotiff/geotiff.html

The OGC OpenGIS activity, through their Earth Imaging Working Group (EIWG), is interested in strengthening the imagery portion of the OpenGIS specification's Open Geodata Model.

Common requirements should also be explored with the hydrographic, maritime, and bathymetric communities, including IHO, IMO, NOAA, NIMA, Coast Guard, and FGDC Bathymetric Subcommittee. These groups have some standards for raster (and hybrid raster-vector) nautical charts related to Electronic Chart Display & Information Systems (ECDIS) and Raster Chart Display Systems (RCDS). These standards include HCRF format for the Admiralty Raster Chart Service (ARCS), DIGEST raster form, and BSB format for Raster Nautical Charts (RNC's). Support for raster-based transactional (change-only) updates to small, indexed areas or tiles, and "print on demand capabilities" are important developments in this community.

The SRPBE may be related to recommendations from the 1992 IDON report on a DIGEST Vector Profile to SDTS that also suggested a DIGEST Matrix Profile and a DIGEST Raster Profile to SDTS. The Raster Product Format (RPF), used for a number of NIMA products (e.g., ADRG), should also be included in the scope of this continuing harmonization activity.

The USGS reached agreement with the National Aeronautics and Space Administration (NASA) in 1993 to harmonize SDTS with the Hierarchical Data Format (HDF) proposed as the distribution format for all Earth Observation System (EOS) data collected by NASA in the future. This harmonization is challenging because HDF and SDTS have differing goals and perspectives, but they also share common raster data structures. The differences preclude complete definition of one in terms of the other. However, the two agencies have agreed to develop a strategy to bring the two standards into alignment. The National Center for Supercomputing Applications (NCSA) was recommended to lead the harmonization study. See the HDF page at

http://hdf.ncsa.uiuc.edu/

"This harmonization study would not propose eliminating either one of these standards, but would focus on overlapping structures and data elements common to both, and would identifyways of bringing the two standards closer together." (Szemraj, 1994). The current goal is to have the appropriate level of SDTS capability available in version 1.0 of the EOS Data Information System (EOSDIS), but no work is presently underway.

The proposed FGDC "Content Standard for Remote Sensing Swath Data" should also be studied for potential relationships to SDTS Part 5. This new swath data model for remote sensing "supports the development of the NSDI by providing a common framework for the organization of a wide range of remotely sensed data. The model will be particularly useful for data from scanning, profiling, staring, or push-broom type remote sensing instruments, whether they be ground based, shipboard, airborne, or space borne." This model will provide "a solid basis from which to develop interoperable data formats for this common form of remote sensing data. The data model shall define the minimal content requirements for a swath and the relationships among its individual components. It shall also discuss the treatment of optional supporting information within the swath model." [text from proposal on FGDC Standards Working Group web pages].