Lidar Coverage in North Carolina
Is your place covered by lidar, which survey flew it, and to what quality level? Search an address and see the lidar behind the USGS 3DEP elevation model at that point.
Check lidar coverage
Search any North Carolina town, street address or landmark. The answer comes from the USGS 3DEP index of lidar work units, which names the survey, its year and its quality level.
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? USGS 3DEP serves lidar-derived elevation across North Carolina: 3.3 ft per pixel where a full-resolution lidar survey exists, about 9.8 ft per pixel where the model is built from older lidar.
- 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, timber harvest, hurricanes and landslides.
- To what quality level? Surveys differ in the specification they were collected to. A higher quality level means more reliable detail, especially under forest.
The search above answers all three for a single point.
How North Carolina was flown
NC OneMap and USGS 3DEP
North Carolina's statewide lidar is published through NC OneMap, the state's open geospatial data portal run by the NC Center for Geographic Information and Analysis, and it is carried by the USGS 3D Elevation Program, which gathers it into one seamless bare-earth model. The 3DEP index records each lidar work unit with its name, the year it was flown, its quality level and its cell size, and those are the figures the checker shows.
More than one work unit for a place
The 3DEP index can list more than one lidar work unit for the same point, so the checker may show several, each with its own year and quality level. The one the seamless model uses there is marked.
When the index cannot be reached
The checker reads the USGS index live. If the index is temporarily unavailable, the result reads “Coverage could not be confirmed” rather than guessing; try again in a few minutes.
One seamless model
Ground elevations on this site come from the USGS 3D Elevation Program (3DEP) seamless bare-earth model: 3.3 ft per pixel where a full-resolution lidar survey has been flown, about 9.8 ft per pixel where the model is built from older lidar, and about 33 ft per pixel elsewhere, with elevations above NAVD 88. The data is in the public domain. North Carolina’s statewide lidar is published through NC OneMap and carried by USGS 3DEP. USGS 3DEP serves lidar-derived elevation across North Carolina: 3.3 ft per pixel where a full-resolution lidar survey exists, about 9.8 ft per pixel where the model is built from older lidar. The 3DEP index records which work unit covers each place, and that is what the checker reads. The state's own lidar downloads are on NC OneMap's elevation page. More from the USGS 3D Elevation Program and NC OneMap’s elevation data.
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 Coastal Plain field, 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 DSM — 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 — every tool on this site |
| DSM | The top of everything: tree crowns, roofs, power lines | Not available for North Carolina; no tool here reads one |
Every tool here reads the bare-earth model, because the questions they answer are about the ground. No DSM of trees and buildings exists for North Carolina, so the Sunlight and Viewshed tools model terrain shadows and lines of sight over the bare ground only.
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.
- NC OneMap elevation — North Carolina's own lidar-derived elevation downloads.
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 full-resolution work unit exists, older lidar at about 9.8 ft per pixel elsewhere, and drops to about 33 ft per pixel only where it has to. The three can meet inside one area you select, so every file from Download Data states what share of its area fell outside the full-resolution lidar work units, 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 North Carolina has lidar coverage?
USGS 3DEP serves lidar-derived elevation across North Carolina: 3.3 ft per pixel where a full-resolution lidar survey exists, about 9.8 ft per pixel where the model is built from older lidar. The state’s lidar is published through NC OneMap and carried by USGS 3DEP. 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 3DEP index records there, each with its name, year, quality level and cell size as the index publishes them.
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, timber harvest, landslides, hurricanes 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 the quality level mean?
The quality level is the USGS grade a lidar survey was collected to: the specification its point spacing and vertical accuracy had to meet. A survey collected to a higher grade resolves ditches, banks and walls more sharply and finds more ground under forest. The checker shows the quality level as the 3DEP index records it; the figures behind it are in the survey’s own USGS metadata.
What happens where there is no lidar work unit?
The USGS 3DEP elevation model is seamless: where no full-resolution lidar work unit exists it is built from older lidar at about 9.8 ft per pixel, and where there is no lidar at all it falls back to 1/3 arc-second data, about 33 ft per pixel. The older lidar is fine for most terrain questions; the coarse fallback 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 fell outside the full-resolution lidar work units.
What is the difference between bare earth and a DSM?
The bare-earth model (DEM or DTM) is the ground with trees and buildings removed. A DSM is the top of everything: tree crowns, roofs and power lines. Use bare earth for contours, drainage and earthwork. No DSM is available for North Carolina, so every tool on this site is bare earth: it reads the USGS 3DEP model and nothing else.
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. County parcel boundaries are the assessor's GIS data compiled by NC OneMap, not surveys, and the county that published each parcel is named with it. The aerial basemap is from Esri and follows Esri's terms; it is not included in downloads.
Related guides
- Lidar data for North Carolina — what lidar is, and what quality level means.
- Download DEM data for North Carolina — bare earth and DSMs 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 North Carolina — every export format and how to pick an interval.