Minnesota, the land of 10,000 lakes, is fortunate to have an abundance of clean, clear water. Our communities have evolved from the benefits and transit capabilities of our waters; many of us still define our lives around the waters in this state. Placing a high value on these water resources, the citizens of Minnesota voted to establish the Clean Water, Land, and Legacy Amendment in 2008. As a result, a portion of the state’s sales tax is dedicated to the Clean Water Fund, which supports projects and products that protect, preserve and improve the water quality of Minnesota.
The Need for Topographic Information
Most, if not all, of these projects require detailed and accurate information that describes the lay of the land. The morphology of the landscape defines how precipitation transforms into flowing water, and subsequently that flowing water shapes the landscape. Detailed topographic information is essential to understanding this dynamic process and the human influences on the hydrologic systems of earth.
To meet this need, a portion of the Clean Water Fund was used to compile a highly detailed and accurate elevation data set for the entire state in a consistent format and to make it readily available without charge to the public.
The U.S. Geological Survey (USGS) 1:24,000-scale quadrangle maps provided the initial coverage of statewide topographic contours. The elevation information was derived from stereo aerial photography generally in the 1960’s and 1970’s. The contours on these 1,745 individual maps also provided 30-meter digital elevation model (DEM) data for the entire state. For many years resource managers and citizens have relied on these base topographic maps for terrain representation, which over time have become increasingly out-of-date. Thanks to advances in technology and the formation of data collection and evaluation partnerships, a new elevation collection project was possible using LiDAR.
This statewide seamless elevation information can be viewed and downloaded through Minnesota’s new elevation portal called MnTOPO.
LiDAR analysis examples
This valuable data is available to the public thanks to cooperative funding initiatives. With oversight from the Minnesota Elevation Committee, Minnesota’s modern elevation mapping project was completed with funding from the Clean Water Fund of the Land and Legacy Amendment. Collections in the northwest and west-central areas were funded through the Red River Basin Mapping Initiative which pooled resources from many funding partners. Collections in the southeast were funded through state flood relief and mitigation monies in response to the 2007 flood. Several counties and cities funded data collections within their boundaries or provided funding to increase the LiDAR point density for their jurisdiction.
Cooperative Quality Control
Quality control was critical to the success of Minnesota’s elevation mapping project. Again, a cooperative approach was taken to bring efficiencies and lower cost into the project under the guidance of MnDOT survey staff. Many counties across the state provided assistance and staff time to gather detailed ground-survey information that was used to verify the accuracy of the data collected by the LiDAR vendors. In other areas, Department of Transportation surveyors gathered this information. This information was then used by Minnesota Department of Natural Resources staff to assess the accuracy of the information and ensure that it was within contractual guidelines.
LiDAR data and its derived products are an emerging and exciting technology that is making its way into the inner workings of planning and GIS analysis worldwide. Project partners recognized that a training program would be an important contribution to the overall success of data users.
Coordinated educational initiatives supported by the MN GIS/LIS Consortium, University of Minnesota, Minnesota Department of Natural Resources, Minnesota Department of Agriculture, Minnesota Board of Soil and Water Resources, and Minnesota LiDAR Research and Education Subcommittee developed several training courses that have been presented at a variety of locations across the state. As a result, users of LiDAR information and derived products have quickly become successful practitioners of the technology to meet their own business needs.
The Minnesota Digital Elevation project is a large and complex project with many different people and agencies involved. If any cooperators were missed on this page please let us know.