The National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center's grab sample data are collected using a variety of small grab sampling devices (such as Ponar and Shipek). The data represent benthic habitats observable at the time of data collection. The grab samples fall into two types: a sediment grab focused on sediment grain size analysis; and a benthic grab focused on identifying biota within the sample.
- Area of Coverage: Varies by project. Normally ranges from minimum depths of -1 meter to -30 meters. Project extents are individual bay systems in Maine, Virginia, New York, New Jersey, and Florida.
- Date(s) Available: Vary by location, ranging from 1995 to 2004
- Format: ESRI point shapefile
- Resolution: Planimetric resolution is based on the size of the grab and normally is approximately .03 meters. Vertical resolution is dependent on substrate type but normally is less than 0.25 meters.
- Accuracy: 100 percent for observed points
- Developed in close cooperation with state and local partners to ensure high degree of accuracy and applicability
- Organized according to the Florida System for Classification of Habitats in Estuarine and Marine Environments (SCHEME) and classified using the Wentworth system
- Analyzed by grain-size distribution and chemical constituents as determined through laboratory analysis
- Evaluated by individual species counts and taxonomic analysis
- Contain a record of all observed organisms to a lowest practical identification level (LPIL)
Data available in:
- Delaware – Delaware Bay
- Florida – Apalachicola Bay
- Maine – Wells National Estuarine Research Reserve
- New York – Jamaica Bay, Hudson River, and Lower Bay
- Virginia – Chesapeake Bay
Notes and Limitations: Benthic and sediment grab point data are normally intended to identify specific sediment and biological characteristics and are collected to complement other sampling or mapping efforts. The data are collected in a systematic pattern distributed through the project area and require some interpolation to generate a comprehensive data set. Interpolations of these data should be used with caution due to potentially large non-sampled areas that are present within the output data. Users are encouraged to develop or obtain higher detail data for non-sampled areas within an interpolated output.
Techniques for Spatial Analysis and Visualization of Benthic Mapping Data
Describes spatial concepts important to data analysis, such as scale, interpolation, and data format
Tools and Techniques for the Acquisition of Estuarine Benthic Habitat Data
Examines the various technologies available for benthic mapping and provides guidance for collecting source data for mapping
Summary View of Grab Sampling Survey Technique
Describes the scale and methods for collecting grab samples
Coastal and Marine Ecological Classification Standard
Provides a comprehensive national framework for organizing information about coasts and oceans and their living systems