PSSatellite Imagery and Visualization of the Caicos Platform*
Paul M. (Mitch) Harris1 and James Ellis2
Search and Discovery Article #50080 (2008)
Posted July 15, 2008
*Adapted from poster presentation at 2008 AAPG Annual Convention
1Chevron Energy Technology Company, San Ramon, CA ([email protected])
2Ellis GeoSpatial, Walnut Creek, CA ([email protected])
The Caicos Platform has proven to be an area of continuing interest to researchers in modern carbonates, an important training venue, and a valuable modern analog for understanding facies patterns of subsurface isolated platforms. We hope to promote this interest by making readily available a set of processed satellite images and an offshore/onshore digital elevation model (DEM), along with examples of how this data can be visualized and used.
The clearest satellite images of Caicos Platform from 1972 to ~2004 were acquired and processed. Image processing was done so that apparent water penetration was maximized and delineation of submerged features was emphasized. The primary images are 30-meter Landsat TM complemented by older 57-meter Landsat MSS and recent 15-meter ASTER. The processed scenes were georeferenced to a base image in GIS, creating a stack of co-registered images that can be effectively used for change detection. Masks were created for water and land to enable integration of different images and maps. Soundings, along with earlier work deriving estimated water depths based on the spectral characteristics of a Landsat TM image, were used to create a digital bathymetric map. This offshore depth map was integrated with an onshore DEM derived from NASA Space Shuttle elevation data (SRTM) for the islands. Various satellite images and maps can be draped on the DEM within the GIS to provide perspective views. To increase accessibility, improve learning, and promote spatially accurate feedback, the stack of images, color-coded DEM, and maps are being exported out of GIS using the free Adobe Reader and TerraGo’s GeoPDF.
Wanless, H.R., and J.J. Dravis, 1989, Carbonate environments and sequences of Caicos platform: 28th International Geological Congress, Fieldtrip Guidebook T-374. 75 p.