Wisconsin Geospatial News

New county image mosaics available from WisconsinView

Earlier this month, the National Park Service (NPS) in Ashland, WI completed work on generating 72 individual county mosaics from a statewide set of 18-inch imagery produced by the 2010 Wisconsin Regional Orthoimagery Consortium (WROC) project. The new mosaics are now available as a free download from the WisconsinView Data Portal.

NPS generated the 72 mosaics in JPEG2000 format with a compression ratio of 10:1, thereby reducing 1.7 terabytes of statewide data down to approximately 269 GB. The mosaics are referenced to a Wisconsin Transverse Mercator (NAD 83) coordinate system.

The original statewide 18-inch resolution product was assembled by the WROC contracting team by resampling high-resolution, high-accuracy imagery acquired over WROC member counties during the spring of 2010, along with additional 18-inch lower-accuracy imagery acquired over counties that did not participate in WROC.

Last July, the public-domain GeoTIFF tiles were made available as a free download from the WisconsinView site. However, at approximately 500 MB each, the original quarter-quad based tiles proved to be too unwieldy for users requiring imagery across large regions.

Many thanks go out to Al Kirschbaum, Remote Sensing Specialist with the National Park Service Great Lakes Inventory and Monitoring Network, and Dr. Sam Batzli, WisconsinView Director, for making this new format available to the Wisconsin geospatial community!