By Jaime Martindale
For nearly 15 years, the University of Wisconsin-Madison has been collecting and archiving state and local geospatial data. While students and researchers may be the primary audience, we hope that as these collections grow, broad use by public audiences looking for historical geographic footprints of places in Wisconsin also grows. Wisconsin maintains a series of “Foundational Layers” which are critical to the flow of annual business applications, information sharing, and other use cases in government agencies across the state. For agencies to provide essential public services to constituents, having reliable geospatial data is important to support functions like 911 emergency response, maintenance and construction of roadways, sidewalks or trails, building new facilities, and smart community planning.
As important is it may be to offer users the latest and greatest versions of foundational layers for current issues and applications, having access to older versions helps us understand the past and how places and features have changed over time. What better way to make intelligent decisions than to understand a community’s past to best determine what it may look like in the future? Users can also access historic aerial imagery and LiDAR elevation data for all of Wisconsin to see physical changes in the landscape and track environmental processes like lake bluff erosion in coastal counties.
Some examples of Wisconsin historic geospatial data in the BTAA Geoportal:
- Land use: Kenosha County, Wisconsin – 1963, 1970, 1980, 1990, 2000, 2010, 2020, 2024
- Roads: Dane County, Wisconsin – 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2023, 2024
- Backshore Condition – Lake Michigan Shoreline 1976 - 2007
- WISCLAND Landcover (WI DNR): 1998, 2016
- Wisconsin Cropland Data Layer (USDA): 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020
Image from ArcGIS Pro of Kenosha County Land Use, 1963
Image from ArcGIS Pro of Kenosha County Land Use, 1990
Image from ArcGIS Pro of Kenosha County Land Use, 2024
While it may not seem significant to see data labeled as “historic” when it is just 10 or 15 years old, the goal of the geospatial archive is to ensure that this digital information remains permanently accessible into the future so users can access it for another 30, 40, or 50 years and beyond. In the same way academic map libraries have maintained print map collections that can be hundreds of years old, we hope to allow users to reconstruct the geographic footprint of places across Wisconsin using foundational geospatial data layers covering a range of time periods.
Visit the BTAA Geoportal (https://geo.btaa.org/) for access to all of Wisconsin’s current and historic geospatial data layers – available for direct download. Each year 500 to 1,000 new datasets are added to the geoportal from the archive at the University of Wisconsin-Madison’s Robinson Map Library.