Interpretation of the sidescan sonar mosaic from the study area off New London, CT, USGS OFR 00-304

This data layer, which focuses on benthic communities, was developed
as part of a cooperative project between the University of New Haven,
the Connecticut DEP, and the U.S. Geological Survey. Benthic
communities are an integral component of the ecology of Long Island
Sound.

Understanding the role that spatial heterogeneity plays in the dynamic
of benthic landscapes may be a key to developing a better
understanding of the estuarine ecology and the impacts of human
activity. The purpose of providing this data layer is to help
establish a regional framework for developing a more extensive GIS for
benthic communities in Long Island Sound that can be used for
education, research, and environmental management.

Mapping was performed on a sidescan sonar survey. This survey was
processed at 3,479-scale utilizing the U.S.G.S. Mini Image Processing
system (MIPS) in an Equatorial Mercator Projection. Processing
included bottom, ratio, and radiometric corrections; sectioning the
survey area; "Geoming" individual map sections; "stenciling" and
"mosaicing"; and building the final image. The shading convention for
this mosaic is that dark tones are interpreted as fine sediment (fine
sand, silt and clay); and light tones are interpreted as coarse
sediment. Rough and "grainy" patches are interpreted as glacial drift
or bedrock outcrops.The image files contained here have been modified,
using Arc/Info software, from the three original TIFFs delivered by
University of Rhode Island. The images were converted to grids,
geo-referenced, and individually reclassified in a manner similar to
linear stretching to account for variations in gray scales among the
three sections of the mosaic. The grids were then converted back to
TIFF format with world files in Latitude/Longitude decimal degrees (no
projection). Pixel size is approximately 0.8 meters.

The original studies were conducted to describe the benthic
communities in Long Island Sound; the corresponding data layer is
presented to show the extent of the sidescan sonar mosaic off New
London, in eastern Long Island Sound, and the distribution of habitats
on the mosaic.

This data layer is an interpretation of the sidescan sonar mosaic from
the study area off New London, CT.