Lidar for Minnesota: How the 3D Elevation Program Pays Off

In Minnesota, high-quality elevation data underpin agriculture and precision farming, conservation, flood risk management, infrastructure and construction, water supply and quality, coastal zone management and many other uses. Many of them depend on lidar — light detection and ranging — which produces a detailed three-dimensional model of the ground and everything on it.

The 3D Elevation Program (3DEP), managed by the U.S. Geological Survey with federal, state, tribal, territorial and local partners, aims to collect consistent lidar nationwide (radar in Alaska) — the first national baseline of high-resolution elevation data, as bare-earth elevation models and 3D point clouds. The data are free and unrestricted, through The National Map.

Quality levels

3DEP baseline data must be quality level 2 or better, with 1-meter or better elevation models, and meet the Lidar Base Specification version 1.2 or newer:

Status of 3DEP baseline lidar data in Minnesota, May 2023: available or in progress everywhere except parts of western and northwestern Minnesota. U.S. Geological Survey.

Minnesota's plan

The Minnesota Geospatial Advisory Council's 3D Geomatics Committee — whose members, from federal, state and local agencies and the private sector, work on lidar standards, data management, funding and education — wrote the Minnesota Lidar Plan (2021), guided by the National States Geographic Information Council. Its goals are quality level 1 lidar, statewide collection within about five years, and more detailed lidar-derived information.

By the numbers

The top uses, by conservative estimate of annual benefit (in millions):

In practice

• Water. Detailed topography is key to understanding how water moves across Minnesota and reducing human impacts such as nutrient and sediment runoff. Denser, newer elevation data save time and make water conveyance features much easier to identify, supporting accurate modeling of surface flow.
• Forests. Forest inventories inform timber estimates, wildfire risk and habitat monitoring, but fieldwork is costly. The Minnesota Department of Natural Resources reported that a pilot using high-density lidar for a model-assisted forest inventory cut costs by about 55%, lidar included, and made it possible to analyze all lands, not just state-managed ones.
• Infrastructure. For more than 40 years the Minnesota Department of Transportation has relied on aerial imagery, photogrammetry and field surveys. Dense lidar can see through gaps in the forest canopy to the ground, letting engineers analyze sites remotely with less field time and risk — identifying archaeological sites to avoid, calculating lines of sight and cut-and-fill for roads, choosing where to build, measuring the heights of existing assets and mapping roads, railroads, levees and buildings in greater detail and at lower cost.

Nationally

Nationwide, 3DEP is conservatively estimated to deliver $690 million a year in benefits, with the potential for $13 billion a year more. Buying data for larger areas cuts costs, and consistent coverage serves projects that cross jurisdictional and watershed lines. Federal, state, tribal, territorial and local governments and private partners can take part — contributing funds to USGS-managed projects, receiving cooperative funds for their own, or contributing existing data that meet 3DEP requirements — through an annual Broad Agency Announcement.

Sources

• U.S. Geological Survey: "The 3D Elevation Program—Supporting Minnesota's economy," Fact Sheet, citing Dewberry (2012), Heidemann (2012), Sugarbaker and others (2014) and the Minnesota Geospatial Advisory Council's Minnesota Lidar Plan (2021). Comments from the Minnesota Geospatial Advisory Council and the Minnesota Department of Natural Resources are paraphrased; an image from the Minnesota Department of Transportation is not reproduced.
• Words on this page from people and organisations outside the federal government are paraphrased; rewritten in hubnx's own words.