Autonomous Surface Vehicle Side-Scan-Sonar Mosaic of Apalachicola Bay, Florida

These data were collected under a cooperative mapping program between the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration Office for Coastal Management (NOAA\OCM), and the Apalachicola National Estuarine Research Reserve (NERR). The primary objectives of this program were to collect marine geophysical data to develop a suite of seafloor maps to better define the extent of oyster habitats, the overall seafloor geology of the bay and provide updated information for management of this resource. In addition to their value for management of the bay's oyster resources, the maps also provide a geologic framework for scientific research and the public.

High-resolution bathymetry, backscatter intensity, and seismic profile data were collected over 230 square kilometers of the floor of the bay. The study focused on the Apalachicola Bay and Western St. George Sound portions of the estuary mostly in depths > 2.0 meters.

Original contact information:

Contact Name: Brian Andrews

Contact Org: U.S. Geological Survey

Title: Geographer

Phone: 508-548-8700 x2348

Email: bandrews@usgs.gov

These data are high-resolution acoustic backscatter measurements over part of Porter's Bar in St. George Sound, Florida. These data were collected using the Autonomous Surface Vessel (ASV) IRIS primarily over known oyster bars in waters less than 1-2 meters deep.

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Side-scan sonar images are grey scale rasters. There are no attributes associated with a GeoTIFF image. Image pixel values contain acoustic reflectivity values normalized to an 8-bit data range (0-255). Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values).

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NOAA manages much of the data to users of digital geographic data.NOAA is in no way condoning or endorsing the application of this data for any given purpose.It is the sole responsibility of the user to determine whether or not the data is suitable for the intended purpose.It is also the obligation of the user to apply the data in an appropriate and conscientious manner.NOAA provides no warranty,nor accepts any liability occurring from any incomplete,incorrect, or misleading data, or from any incorrect,incomplete, or misleading use of the data.Much of the data is based on and maintained with ARC/GIS software developed by the Environmental Systems Research Institute (ESRI).In addition, much of the information presented uses conventions and terms popularized by ARC/GIS and its user community. NOAA in no way represents the interests of ESRI,nor acts as agents for them. The user must have software capable of viewing a GeoTIFF data file.

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Data are not intended for navigational use.

These data should not be used at resolutions for which it is not intended.

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350

Not relevant to this data set.

The ASV used RTK-GPS for navigation. RTK-GPS is assumed to be accurate within 1-2 meters. All GPS/DGPS data are referenced to WGS84. The sidescan-sonar transducers are mounted on a metal frame between the two pontoons about 0.5m below water surface, and directly below the GPS antenna..

Although both the 100 kHz and 400 kHz frequency data were collected, only the high-frequency 400 kHz data were processed and included in this mosaic. Small differences in contrast stretch (DN values) exist because of variations in sea and weather conditions on each survey day.

Not applicable for raster data.