The T-sheets are detailed survey maps issued by the National Oceanic and Atmospheric Administration's (NOAA) National Ocean Service (NOS), formerly the U.S. Coast and Geodetic Survey (USC&GS). These maps were produced to provide coastlines for use on navigation charts and contain survey marker locations, lines of latitude and longitude, and a representation of vegetation inland from the coast. Most of the South Florida maps on this CD are at 1:20,000 scale, except 3 maps at 1:10,000 in the Sanibel Island vicinity not included as part of the digital mosaic. The maps are based on aerial photography from 1925 to 1935. The maps were published upon completion, some as early as 1931 and others based on supplemental survey data completed in October, 1940.
Analyses of information contained in historical aerial photographs of the Everglades can aid in this endeavor. For example, the earliest known aerial photographs are from the mid to late 1920s and resulted in the production of what are called T-Sheets (for Topographic Sheets) for the coasts and shorelines of far south Florida. Importantly, the position of the boundary between differing vegetation communities (the ecotone) can be accurately measured. If followed through time changes in the position of these ecotones could potentially be used to judge effects of drainage on the Everglades ecosystem and also to monitor restoration success.
The Florida Caribbean Science Center (FCSC), a center of the U.S. Geological Survey's (USGS) Biological Resources Discipline (BRD) has created digital versions of existing topographic survey (T-sheets) for the Florida Everglades region. These digital files are available in a manner designed to facilitate access to the product by those intending to integrate the data with other spatial data, specifically those interested in the impacts of global climate change and land use change on coastal ecosystems.
Although the data published herein has been reviewed by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related material. Publication and distribution of these data should not be construed to constitute any such warranty and no responsibility is assumed by the USGS in the use of these data or related materials.
2) Scanning of paper maps The sheets were scanned at a resolution of 400 x 400 dpi. The files were saved in tagged image file format (*.tif). Scanning was completed in 2001 by C. Van Arsdall at the USGS National Center in Reston, VA.
3) Converting Control points to UTM Zone 17N, NAD 27 Control points were converted to UTM coordinates before resampling the images.
4) Georeferencing the images Paper historical T-sheet maps contain lines of latitude and longitude among other survey data. These lines were used to georeference the sheets using ERDAS IMAGINE (TM) 8.4 software. A minimum of 4 control points were used to reference each image, with a RMS error <.05 pixels accepted.
Georeferencing and CDROM were completed in 2001 by P. Briere at the FL Caribbean Science Center in Gainesville, FL.
Files not georeferenced have the following naming convention, T-4371.tif.
Georeferenced files (GEOTIFFs) are in a compressed form and when uncompressed have the following naming convention, 4371_geo.tif. The paper maps were based upon NAD 27 and this datum was retained in the GEOTIFFs.
Most of the paper maps were drawn to a scale of 1:20,000. Three of the maps (5862, 5863, 5866) at the northern extent of the study area were drawn at 1:10,000. These maps were not included in the mosaic. They are included as individual GEOTIFFs.
The T-sheets between 4371, 5866, and 5863 are not included on the CD. They currently do not reside in the T-sheet set at the U.S. Geological Survey, Biological Resources Division, Florida Caribbean Science Center.
The mosaic GEOTIFF covers a large regional extent, and when viewed at a reduced scale may not appear to have any data associated with it. For optimal viewing of the data, view at full resolution. The mosaic was resampled with an output cell size of 5m x 5m to produce a file of usable bulk.
Specific information regarding aerial photography dates varies by map and is located on each map in both paper and digital form, except the digital mosaic. This information was cropped to produce a mosaic with minimal collar (white space) and maximum vegetation data.
Although the data published herein has been reviewed by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related material. Publication and distribution of these data should not be construed to constitute any such warranty and no responsibility is assumed by the USGS in the use of these data or related materials.
Although the data published herein has been reviewed by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related material. Publication and distribution of these data should not be construed to constitute any such warranty and no responsibility is assumed by the USGS in the use of these data or related materials.
Although the data published herein has been reviewed by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related material. Publication and distribution of these data should not be construed to constitute any such warranty and no responsibility is assumed by the USGS in the use of these data or related materials.
Although the data published herein has been reviewed by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related material. Publication and distribution of these data should not be construed to constitute any such warranty and no responsibility is assumed by the USGS in the use of these data or related materials.
U.S. Department of the Interior, U.S. Geological Survey, Center for
Coastal Geology
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