Bathymetry of Lake Michigan

Download Bathymetry Contours in ESRI Shapefile Format (13.9MB)

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CD-ROM/Poster Ordering Information and Online Store

Products Available:

• A full color poster (34x45 inches) [Preview Lake Michigan Poster (53K gif)]
• A full color wall-size poster (4x8 feet when assembled) at a scale of 1:250,0000
  • Preview Wall-Size Poster (466K jpg)
  • PDF Wall Size Poster in 3 parts:
    • top (4 Mb),
    • middle (2 Mb),
    • bottom (1.3Mb)
• A CD-ROM containing data & images [On-line Sample of CD-ROM]

The online sample offered in the link above demonstrates the interface that accompanies the Bathymetry of Lake Michigan CD-ROM. Links to page size and expanded .GIF images of bathymetry are live in the online demonstration, and images are available for download. Higher resolution .EPS and .JPEG versions of the images are only available on the CD-ROM due to their large size. Links to raster and vector data file are also not active in the online demonstration. For a full description of the Bathymetry of Lake Michigan CD-ROM and accompanying full-size poster, please follow the Data Announcement link above."

Bathymetry of Lake Michigan 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 and Geophysics Division (NGDC/MGG) and the NOAA Great Lakes Environmental Research Laboratory (GLERL). was compiled utilizing the entire historic sounding database. This bathymetry resolves physiography of the lake floor to an extent that known features are revealed more accurately and features never before seen are revealed for the first time. Bathymetry has been compiled using the entire array of good-quality historical hydrographic soundings collected in support of nautical charting over a 120-year period by the NOAA National Ocean Service and its predecessor agency for Great Lakes surveying, the Army Corps of Engineers. More than 600,000 bathymetric soundings were employed, of which approximately 60 per cent were already in digital form, 25 per cent were digitized in conjunction with this effort, and the remaining 15 per cent were available only on paper survey sheets.

Bathymetry was compiled at a scale of 1:250,000, with a contour interval of 5 meters. Density of tracklines is generally about 2000m for the open lake and ranges from 200m to 600m for nearshore areas. Soundings collected since 1903 were already reduced to the Lake Michigan mean low water datum; these were used for bathymetric contouring without further calibration or adjustments. Soundings collected prior to 1903 were reduced to the mean low water datum. In preparation for bathymetric contouring, digital soundings were converted to metric units and plotted in color; separate colors were assigned to the various depth ranges. From the paper sheets, contours in metric units were generated directly on overlays; these contours were then reduced to the compilation scale of 1:250,000 and incorporated into the map. Compilation sheets were then scanned and vectorized; and the resulting digital vector bathymetric contour data were used to generate the imagery shown on the large color plate. Images were constructed using the publicly-available software Generic Mapping Tools (GMT)

Click on the image above for a larger view of the bathymetry of Lake Michigan.

GEODAS Desktop Software is a user friendly software package which can be used to view, revise, subset and re-format GRD98, ARC ASCII and Binary grids.

Great Lakes Bathymetry Page