| Bathymetry of Lake Ontario |
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Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue
Great Lakes lake floor geological and geophysical data and make it more accessible
to the public. The project is a cooperative effort between investigators at the NOAA
National Geophysical Data Center's Marine Geology & Geophysics Division (NGDC/MGG)
and the NOAA Great Lakes Environmental Research Laboratory (GLERL). was compiled utilizing
the entire historic sounding data base. The entire historic hydrographic sounding
data base from the U.S. and Canada, originally collected for nautical charting purposes,
was used to create a complete and accurate representation of Lake Ontario bathymetry.
The U.S. data primarily came from the NOS Hydrographic Survey Data. This and other
bathymetric sounding data collected by the U.S. National Ocean Service's (NOS) Coast
Survey and the U. S. Army Corps of Engineers was employed to construct bathymetric
contours at 1 meter intervals from 1-10 meters depth and 2 meter intervals at depths
greater than 10 meters. Compilation scales ranged from 1:10,000 to 1:50,000. Bathymetric
sounding data collected by the Canadian Hydrographic Service (CHS) were employed to
construct bathymetric contours at 1 meter intervals and compilation scales ranging
from 1:1,000 to 1:30,000. Digitization of the bathymetric contours, merging of the
bathymetric contour data sets, poster construction, and preparation of a CD-ROM, were
accomplished at the NGDC. Multibeam bathymetric data collected by the University of
New Brunswick's Ocean Mapping Group (UNB-OMG), with support of the Geological Survey
of Canada (GSC) and the CHS, were kindly made available in gridded form. In the two
areas where multibeam bathymetric data were available, no other bathymetric data were
used in the compilations. In some areas all available Canadian and U. S. bathymetric
sounding data, collected at different times on different survey expeditions, were
used to derive the contours. The U.S. coastline used was primarily the GLERL Medium
Resolution Vector Shoreline dataset (Lee, 1998). Where needed for more coverage, the
NOS Medium Resolution Vector Shoreline for the Conterminous U.S. (1994) dataset was
used. Coastlines from the CHS bathymetric sounding data field sheets were used to
complete the Canadian coastline. Images were constructed using the publicly-available
software Generic Mapping Tools (GMT). |
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