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Featured collections: LiDAR and Aerial Imagery Collections for Wisconsin

 By Jaime Martindale.

In recent years, the University of Wisconsin-Madison has made improving access to LiDAR and aerial imagery a priority in the B1G Geoportal. Building on the popularity of the historic 1937-1941 aerial photos of Wisconsin, (one of the most popular resources in the B1G Geoportal for several years running) our current focus has been on enhancing discovery to more current aerial imagery and LiDAR elevation data currently housed within the WisconsinView repository. (part of the University of Wisconsin-Madison’s Space Science and Engineering Center) serves as the repository for remotely sensed data in Wisconsin -- from LiDAR and satellite imagery, to digital orthophotography, tornado and flood data. In partnership with WisconsinView, the UW Robinson Map Library and WI State Cartographer’s Office are working to write metadata and facilitate access to these collections via the B1G Geoportal. This work results in greater exposure to the data and imagery, and combines access to additional data and resources in the geoportal that may be useful in conjunction.

LiDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. Example derivative datasets from LiDAR include Digital Elevation Models (DEM), Digital Surface Models (DSM), derived terrain, contours, and classified point cloud data that can be interpreted in many ways. At present, there are nearly 700 LiDAR datasets for Wisconsin in the B1G Geoportal.

Sample LiDAR dataset for Columbia County, Wisconsin in 2011.
Wisconsin is fortunate to have several sources of digital aerial imagery products (at varying resolutions) from federal, state, and local government sources. Aerial images from 2004-present now total over 1,500 datasets in the B1G Geoportal.

Imagery from the National Agriculture Imagery Program (NAIP) and Wisconsin Regional Orthophoto Consortium (WROC) make up a large percentage of the data available, and can be accessed as countywide files or by digital ortho-quarter-quad (DOQQ) tiles. Easy-to-use indexes appear in the geoportal records to determine the appropriate desired tiles. Local imagery obtained by counties is also available, including this example of 3-inch resolution imagery for Iron County for 2020.

3-inch resolution imagery for Iron County in mrsid format from the B1G Geoportal.

Future work will include adding additional historic aerial imagery collections from the Wisconsin Department of Natural Resources Forestry Division, 2020 WI Regional Planning Commission aerial imagery, along with new high-resolution LiDAR data being acquired by Wisconsin counties each year. Look for Wisconsin imagery and elevation collections in the G1G Geoportal to grow at faster rates in the coming years as new data is made available.