USGS 3DEP elevation data is the national set of high-resolution terrain measurements collected by the U.S. Geological Survey’s 3D Elevation Program, mostly with airborne lidar. It is free to use, and it is the source behind every contour design on Map Gift Store. Here is what the program is, what it publishes and how a topo design is drawn from it.
What 3DEP is
USGS says the 3D Elevation Program exists to respond to growing needs for current, high-quality topographic data, and to produce three-dimensional representations of the nation’s natural and constructed features. It is the elevation component of The National Map, the USGS system for distributing base map data.
The program also works with partners. USGS describes collaborating with other federal agencies and others through a Data Collaboration Announcement to fund new collection. The agency’s own page points to a national study that documented $13.5 billion in benefits across 1,352 mission-critical requirements, which gives a sense of how widely the data is used.
How the data is collected
For the lower 48 states, lidar point clouds are the foundation. USGS calls them the foundational data for 3DEP in the conterminous United States. An aircraft sends laser pulses toward the ground and records the returns, building a dense cloud of points that can be classified into ground, vegetation and buildings.
Quality varies by when the data was flown. USGS notes that most data collected in 2014 and later meets 3DEP specifications for quality level 2, while data collected before 2014 often does not. In Alaska, the program relies on IfSAR, a radar method, and publishes 5-meter elevation models there.
The elevation models 3DEP publishes
Point clouds are turned into digital elevation models, or DEMs: grids where every cell holds a ground height. USGS lists these main products:
| Product | What USGS says about it |
|---|---|
| Seamless 1-meter DEM (S1M) | The highest-resolution seamless elevation dataset 3DEP produces for the nation, built from many lidar projects |
| 1-meter DEM (project-based) | Introduced in 2015 with limited coverage, expanding over time |
| 1/3 arc-second DEM | A medium-resolution seamless dataset, with coverage that includes Alaska, Hawaii and territories |
| 1/9 arc-second DEM | Project-based, covers about 25 percent of the conterminous U.S., no longer updated with new DEMs |
| 1 arc-second DEM | A lower-resolution seamless dataset covering the conterminous U.S. and Alaska |
All of these are distributed through The National Map in tiles that can be merged across large areas, and USGS states that every 3DEP product is available free of charge and without use restrictions.
From elevation grid to contour design
A contour line is simply every point at one chosen elevation, joined together. Software reads the DEM, picks a set of evenly spaced heights, and traces where the ground crosses each one. Our post on what contour lines mean walks through how to read the result.
For a gift design, a few choices shape the look:
- The frame: how much ground around the summit, ski hill or park to include.
- The interval: the elevation step between lines, set so the place reads clearly at print size.
- Smoothing: the raw data captures small bumps that look like noise at gift scale, so lines are cleaned up.
- Style: line weight and color, and whether the art is drawn for light or dark products.
The same data can make a crisp design of a steep peak such as Black Elk Peak or a lower, rolling one like Loess Hills State Forest in western Iowa, where the hills rise about 200 feet above the plains. Places with strong relief, such as the bluffs of Wyalusing State Park or the ski runs of Mont Ripley, tend to produce the busiest designs.
What the designs leave out
The designs keep the land and drop almost everything else: no roads, no trail lines, no labels, no buildings. That makes them good art and poor maps. They are not meant for navigation or trip planning.
If you want to see the source data for a place yourself, The National Map is the public route to it. If you want it on a shirt, mug or canvas, start with a state page such as Michigan topo maps or browse by mountains and high points. More on our process is on how the maps are made.
Every product is printed to order, and final price, sales and shipping are shown at checkout.
Frequently asked questions
What does 3DEP stand for?
3DEP is the U.S. Geological Survey’s 3D Elevation Program. USGS describes it as the elevation component of The National Map.
Is 3DEP data free?
Yes. USGS states that all 3DEP products are available free of charge and without use restrictions.
What resolutions does 3DEP offer?
USGS lists several digital elevation models, including a seamless 1-meter dataset built from lidar, a 1/3 arc-second seamless dataset, a 1 arc-second dataset and project-based 1-meter and 1/9 arc-second models.
Are designs drawn from 3DEP accurate enough to navigate with?
No. The source data is high quality, but our designs are simplified art with no trails, roads or labels. Use a current map for any outdoor trip.