National SDTS Implementors' Workshop Results

SDTS Workshop Results - Technical Session

Speaker: Mike Ruth, Spot Image

1897 Preston White Dr.
Reston, VA 20191
(703) 715-3146

Presented by: Dr. David K. Arctur

Topic: GeoTIFF Format for Raster Geographic Imagery

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

What is TIFF format? TIFF stands for "Tagged Image File Format" and is a rich format for raster image data. TIFF is licensed by Adobe Corporation, including TIFF tags and documentation. The tags consists of public (what the general industry agrees on) and private (internal) tags to support imagery. Anyone can extend tags by petitioning to Adobe. TIFF format is already widely used by many geographic systems suitable for both "high-end" and "low-end" systems and functions as a transfer format as well as being efficient for direct use. TIFF has been stable for many year, supports tiling and compression and is supported by many public domain libraries.

Why GeoTIFF format with SDTS? It offers interoperability across platforms and is an internationally accepted image format. GeoTIFF offers all the benefits of TIFF plus additional information such as: geographic metadata, hierarchic geodesy model, 64 bit precision support, transformation matrix support, public entabulation of geographic variables, public software library, and is extensible.

So where are we going from here? GeoTIFF is an informal standard which provides interoperability of projected imagery across many software vendors - and it works. It would be very worthwhile to generate GeoTIFF from SDTS raster data to avoid duplication. The next step is to incorporate GeoTIFF concepts, capabilities, and data content into the SDTS Raster Profile without loss of information. There are two options to harmonize SDTS and GeoTIFF: 1) Fold GeoTIFF completely into SDTS and have the Raster Profile fully represent the GeoTIFF content and look like SDTS. However, this gets away from the direct use capability of GeoTIFF. 2) Use SDTS for those things not in GeoTIFF, like the metadata. Users would get metadata in SDTS and use SDTS readers for that information.

General comments from the audience: Compared to SDTS GeoTIFF is mature and widely implemented. USGS DRG's are in GeoTIFF now and those datasets can be read by TIFF shareware readers. USGS will be offering their DOQ's in GeoTIFF in the near future.

U.S. Department of the Interior || U.S. Geological Survey
1400 Independence Road, Rolla, MO 65401
For general information call: (573)308-3500
URL: http://mcmcweb.er.usgs.gov/sdts/result/technical/geotiffresult.html
Last modified: Monday, 10-Nov-1997 13:59:25 EST
Maintainer: mcmcweb@usgs.gov
Privacy Statement || Disclaimers || FOIA || Accessibility

sdts@usgs.gov