USACE - Detroit District - USACE Detroit District GIS Activities

USACE Detroit District GIS staff have been assembling a range of geospatial data over the course of the LMPDS. This consists primarily of:

Digital Elevation Model coverage (DEM);
Digital Ortho Photos (DOP); and Digitial Orthophoto Coverage
Digital Raster Graphics (DRG)

Digital Elevation Model Coverage
	The figure to the left presents a representation of the status of DEM coverage for the Lake Michigan shoreline. DEMs exist for the majority of the shoreline. Level 1 or Level 2 DEMs (Orange)are available for the entire Wisconsin, Illinois and Indiana shoreline. The majority of the Michigan shoreline has Level 2 DEMs available (Yellow), except for the counties of Delta, Manistee, Mason, Oceana and Berrien where Level 1 DEMs (Green) exist. There are only minor portions of Schoolcraft, Mackinaw and Manistee counties where DEMs do not exist but have been authorized (Blue). For coastal townships in the Michigan prototype counties of Allegan and Ottawa, new aerial photos and DOPs were created at a scale of 1"="200" in 1999. Using this new photography, DEMs were developed for the coastal townships in Allegan and Ottawa counties.

Digital Ortho and Digitial Orthophoto Coverage
	The figure to the left presents a representation of the status of DOQQ and DOP coverage for the Lake Michigan shoreline as of July 2000. USGS DOQQs have been completed (Blue) for a number of counties in Wisconsin, Illinois, and Michigan. USGS DOQQs are being completed (Orange) for Kewaunee County in Wisconsin. USACE DOQQs are completed (Red) for a number of counties in Michigan. Finally, high resolution DOPs (Gray) exist for Kenosha, Racine, Milwaukee and Ozaukee Counties in Wisconsin and Berrien County in Michigan. New, high-resolution digital orthophotos will be developed in the five prototype counties and, subsequently, for the remaining Lake Michigan counties. These photos will be used in subsequent tasks to develop bluff line mapping, to map structures, to update land use mapping, and to be used as a base map. Digital orthophotos, created at 1"="200," were created for the two Michigan prototype counties from photography flown in 1999. Recent digital orthophotos for the Wisconsin prototype counties and other coastal counties in Wisconsin were coordinated by the University of Wisconsin.

Digital Raster Graphics
	A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) standard series topographic map (left), including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch. A DRG can be used on-screen to collect, review, and revise other digital data, especially digital line graphs (DLG). When the DRG is combined with other digital products, such as digital orthophoto quadrangles (DOQ) or digital elevation models (DEM), the resulting image provides additional visual information for the extraction and revision of base cartographic information.

	DRGs for the majority of the Lake Michigan shoreline (excluding the northeast portion of the Lake) are available online from the USGS-Environmental Management Technical Center . USACE Detroit has downloaded these DRGs with the intent of using them as baseline and backdrop mapping for other mapping initiatives in the LMPDS.

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