Gridded side-scan imagery collected in Apra Harbor, Guam U.S. Territory, USA. The GeoTIFF and Arc ASCII file includes data that were collected using a Klein 3000 high-resolution side-scan sonar system with dual operating frequencies of 100 and 500 kHz. The data were collected in 2008 by the NOAA Office of Coast Survey and the United States Navy Fleet Survey Team and were preliminarily processed by NOAA OCS using the Caris software. Additional processing and mosaicking was performed by the NOAA Coral Reef Ecosystem Division.
The GeoTIFF and Arc ASCII of side-scan imagery were created using data gathered from multibeam soundings for use as a planning and reference document. The data are also being used for benthic habitat mapping, for locating Essential Fish Habitat, and for studying geologic features of the area. Refer to the supplemental information for instrument and survey information.
Survey data were acquired by the United States Navy (USN) Fleet Survey Team (FST) with Survey Vessel Swamp Fox. The Klein 3000 Side Scan Sonar is operated in the stern-towed configuration. Additional detailed information on data acquisition, equipment configuration, and corrections can be found in the Data Acquisition and Processing Report (DAPR) that can be accessed at: www.soest.hawaii.edu/pibhmc and is included in the ZIP file containing the side-scan GeoTIFF.
ground condition
These data are not to be used for navigation purposes. Please acknowledge NOAA (Office of Ocean Exploration and the Pacific Islands Fisheries Science Center) and the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii, the NOAA Office of Coast Survey, and the USN Fleet Survey Team as the sources of this information.
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http://www.soest.hawaii.edu/pibhmc/CNMI_images/apra_ss_1m_445.jpg
Benthic Habitat Mapping Group, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA and the Joint Institute for Marine and Atmospheric Research (JIMAR) are the sources of this information.
Data are collected for resource management and research purposes and are tested for internal consistency; however, no effort is made to compare these data to external references or to other published data.
These data are believed to be logically consistent though no tests were performed
Complete
Horizontal positioning system: see DAPR Horizontal position accuracy: see DAPR
see DAPR Range resolution of sonar: see DAPR Raw sounding resolution: see DAPR Vertical accuracy of gridded product: see DAPR
The Klein 3000 system consists of a Klein towfish, a Transceiver/Processing Unit (TPU), and a computer for user interface. The along-track resolution is approximately 30cm at the 100m range scale, even when acquiring data at speeds up to 10 knots. Across-track resolution is typically 7.5cm at the 100m range scale. The achievable 0.3m resolution meets the OCS Hydrographic Surveys Specifications and Deliverables Manual for object detection. ISIS Sonar Pro is used to acquire data with the Klein 3000 SSS. Sonar Pro is a Windows-based acquisition software package that provides real-time data display and sonar control. Sonar Pro is used to acquire Klein 3000 data in XTF format. Data acquisition is monitored real time by a qualified sonar operator. The primary user settings that are adjustable during SSS acquisition are the range scale and the resolution. Typically, the range scale and resolution are set prior to logging data and not changed again until the surveyed depth area changes. Caris HIPS/SIPS (Hydrographic Information Processing System/ Side-scan Information Processing System) is used for processing, correcting, and analyzing all bathymetric, side scan, and phase-differencing bathymetric sonar data. Caris SIPS is used for converting and correcting side-scan sonar imagery and for contact selection and mosaic generation. After acquisition, SSS data are converted from XTF format to Caris HDCS format. Fish height, vessel heading (gyro), and vessel navigation records are then reviewed and corrected and recalculated. Data are then slant-range corrected to 0.1m with beam pattern correction. Side scan mosaics were created using the SIPS side scan editor. Mosaics consisted of combinations of lines that resulted in a seamless product after interpolation was applied during GeoBAR creation in Caris SIPS. Since the dataset is so large, a final mosaic was created using ArcGIS 9.x Raster Dataset Tools in the Toolbox. See the SWAMPFOX Data Acquisition and Processing Report included in the side-scan data download ZIP file (apra_ss_1m.zip) available from http://www.soest.hawaii.edu/pibhmc.
Backscatter data within a GSF file are arranged as small sequences of intensity values, one sequence per beam per ping. The intensity values represent the amplitude of echo returns to the sensor and can be related to seabed hardness and roughness.
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These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
TIFF is a format for storage, transfer, display, and printing of raster images. The TIFF file structure allows both the tag and the image data to be encoded into the same file. GeoTIFF refers to a TIFF file that has geographic data embedded as tags within the TIFF file. The geographic data can be used to position the image in the correct location and geometry on the screen of a geographic information display. Any GIS, CAD, Image Processing, Desktop Mapping and other types of systems using geographic images can read any GeoTiff file. More specifically, files of this type can be added to ArcInfo and ArcView 8.x or higher and may be viewed in the Table of Contents as a new raster layer. Image visualization software that does not use geography as a basis for image placement can view a GeoTIFF image as if there were no geographic information in the TIFF file. For example, GeoTIFF files can be viewed using Windows Picture and Fax viewer.The GeoTIFF format is public domain, non-proprietary.
The Arc ASCII file, for use in ESRI's (http://www.esri.com) GIS software, can be converted to an Arc Raster Grid using ArcToolbox ASCII to Raster conversion tool.
