Lidar Coverage in Wisconsin
Is your place covered by lidar, which project flew it, and how dense is the data? Search an address and see the lidar behind the USGS 3DEP elevation model at that point.
Check lidar coverage
Search any Wisconsin town, street address or landmark. The answer comes from the USGS 3DEP index of qualifying fine-resolution work units. Older lidar or coarser terrain data can exist outside those footprints.
Coverage is a question with three parts
“Is there lidar here?” sounds like a yes or no, but the answer that actually helps has three parts.
- Has the area been flown at all? Almost all of Wisconsin has. Lidar coverage and source dates vary across Wisconsin. Check your site against the USGS 3DEP work-unit index; an unavailable lookup means coverage is unknown.
- When was it flown? This decides whether you can rely on the data for a decision. An elevation model shows the ground on the day it was flown, and the ground changes with grading, building, logging and landslides.
- How dense is the data? Point density varies from project to project. More pulses per square foot means more reliable detail, especially under forest.
The search above answers all three for a single point.
How Wisconsin was flown
Project by project
Wisconsin's lidar was flown one project at a time, many of them county by county, and each project has its own specifications. The USGS 3DEP index records the work units, with details such as year, quality level and point density where they are known, and those are the figures the checker shows. The State Cartographer's Office keeps a directory of Wisconsin elevation and lidar data for the county products behind them.
More than one project for a place
The index can list more than one lidar work unit for the same point, so the checker may show several, each with its own year. The checker marks the newest qualifying one; the seamless model does not always say which source it used.
One seamless model
Ground elevations come from the USGS 3D Elevation Program (3DEP) seamless bare-earth model, with elevations above NAVD 88. Source cells are 3.3 ft per pixel in the finest work units, with about 9.8 ft per pixel and 33 ft per pixel sources elsewhere. USGS elevation data is public domain. Lidar coverage and source dates vary across Wisconsin. Check your site against the USGS 3DEP work-unit index; an unavailable lookup means coverage is unknown. The 3DEP index records which work unit covers each place, and that is what the checker reads. More from the USGS 3D Elevation Program and Wisconsin elevation resources.
When the data is old or coarse
Coverage decides how much you can read into a result:
- Fine contours need lidar. An interval of 1 or 2 ft only means something where the model rests on lidar.
- Slope on gentle ground is sensitive. On a nearly flat field in the Central Sands, the noise in a coarse model can be larger than the slope itself.
- House sites, drainage and earthwork need detail. A foot or two matters, and that takes good lidar.
- Recent changes do not show. If a lot was graded, filled or built on after the flight, the model shows the ground as it was before.
Bare earth or surface model — which do you need?
| Product | What it shows | Use it for |
|---|---|---|
| Bare earth (USGS 3DEP) | The ground, with trees and buildings removed | Contours, slope, drainage, cut and fill, flow paths |
| Surface model (Brown County only) | The top of everything: tree crowns, roofs, power lines | Sun and shade, views over trees, object heights |
Most tools here read the bare-earth model, because the questions they answer are about the ground. The surface model covers Brown County only, so Sunlight, Viewshed and Sightline use bare earth everywhere else, and Object Heights works only there.
Where the data lives
- The National Map Downloader — USGS's download tool for 3DEP elevation tiles and lidar point clouds.
- 3DEP elevation index — where each resolution of 3DEP data exists, as a map service.
- Wisconsin elevation and lidar data — the State Cartographer's Office directory, including county lidar.
Read more in the guides to free elevation data and to downloading DEM data.
Working with coverage in this tool
Every result on this site reads the USGS 3DEP seamless model, which uses lidar at 3.3 ft per pixel where a work unit exists and drops to about 33 ft per pixelonly where it has to. The two can meet inside one area you select, so every file from Download Data states what share of its area fell outside full-resolution lidar, and you always know which data a number rests on.
Found lidar over your place?
Draw an area and get contours, slope, drainage or a full property report from the same data. No account and nothing to install.
Frequently asked questions
How much of Wisconsin has lidar coverage?
Lidar coverage and source dates vary across Wisconsin. Check your site against the USGS 3DEP work-unit index; an unavailable lookup means coverage is unknown. Wisconsin’s lidar was flown project by project, many of them county by county. The fastest way to know about a specific place is to check it in the search at the top of this page.
How do I find out when the lidar over my property was flown?
Search your address above. The checker reports whether the point sits inside a USGS 3DEP lidar work unit and lists the work units the USGS index records there, with the year, quality level, cell size, point density and reported vertical accuracy where the index records them, plus a link to the project metadata when there is one.
Why does the flight year matter?
An elevation model is a snapshot of the ground on the day it was flown. Grading, new roads, fill, logging, landslides and rivers that move all change the ground afterward. A survey flown before a lot was graded will not show the grading. When you plan, apply for a building permit or estimate earthwork, the flight year tells you how far you can trust the contours.
What does point density mean?
Point density is how many laser pulses were recorded per square foot of ground. Denser data gives more ground hits under forest and sharper detail in ditches, walls and banks. Both dense and sparse projects can produce the same bare-earth grid, but the dense one is more reliable in the details, especially under forest canopy.
What happens where there is no lidar work unit?
The USGS 3DEP elevation model is seamless: where no lidar work unit exists, it falls back to 1/3 arc-second data, about 33 ft per pixel. That is fine for a picture of the landscape and not for detail that turns on a foot or two — fine contour intervals, slope on gentle ground or siting a house. Every file from Download Data states what share of its area came from the fallback.
What is the difference between bare earth and a surface model?
The bare-earth model (DEM or DTM) is the ground with trees and buildings removed. A surface model (DSM) is the top of everything: tree crowns, roofs and power lines. Use bare earth for contours, drainage and earthwork; use the surface model when what stands on the ground matters, such as shade, a view over a tree line or roof heights. This site reads USGS 3DEP for bare earth everywhere, and Brown County’s lidar surface model for the tools that need trees and buildings in that county only.
Is the data free to use, and who do I credit?
USGS 3DEP elevation data and USGS maps are U.S. Government works in the public domain: you may use the results, including commercially. A credit to the USGS 3D Elevation Program is appreciated, and every file you download carries it. Wisconsin parcel boundaries are aggregated local-government data, not legal surveys; the parcel disclaimer accompanies the selection. Brown County surface data is credited separately when used. The Esri aerial basemap follows Esri’s terms and is display-only; downloadable aerial photos use USGS NAIP.
Related guides
- Lidar data for Wisconsin — what lidar is, and what point density means.
- Download DEM data for Wisconsin — bare earth and surface models explained, and how to get the raw files.
- Slope maps for building — why flight year and resolution matter on a sloping lot.
- Contour map of your property — contours over the county parcel.
- Contour lines for Wisconsin — every export format and how to pick an interval.