USGS 3DEP Download and Formats: Elevation, LiDAR, and DEM Data for GIS
The USGS 3D Elevation Program (3DEP) is the federal elevation-data program for the United States. Its downloadable holdings include LiDAR point clouds, digital elevation models, source-resolution elevation products, seamless DEMs, Alaska IfSAR products, metadata, and elevation query services. Users can access data through The National Map Downloader, LidarExplorer, EarthExplorer, USGS ScienceBase, web services, and cloud-oriented formats. The most important format distinction is between point-cloud data, generally distributed as compressed LAZ, and raster elevation products, increasingly delivered as Cloud Optimized GeoTIFF. 3DEP data is free and in the public domain, but coverage, acquisition date, resolution, vertical accuracy, coordinate reference system, and product lineage vary by location and product.
USGS 3DEP is best understood as a family of elevation datasets and delivery services rather than one uniform national file. It combines airborne LiDAR and, in Alaska, interferometric synthetic aperture radar (IfSAR) products with derived digital elevation models used for terrain mapping, hydrology, engineering, environmental analysis, emergency management, and three-dimensional visualization. The download workflow begins with a geographic area and an intended measurement: raw or classified point observations, a bare-earth elevation surface, a seamless national DEM, or a single-point elevation query. Choosing the wrong product can lead to avoidable errors—for example, using a digital surface model where a bare-earth terrain model is required, or treating a 30-meter seamless DEM as equivalent to a local 1-meter LiDAR-derived surface.
How EDK fits
For: GIS analysts, remote-sensing practitioners, cartographers, civil and environmental engineers, hydrologists, researchers, public agencies, developers, and location-data teams that need authoritative U.S. elevation data for mapping or geographic computation.
Elevation is one of the clearest examples of how geographic data becomes computable. Roads, buildings, waterways, infrastructure, land parcels, vegetation, and administrative areas all occupy a three-dimensional physical landscape, and 3DEP provides terrain measurements that can be attached to those features. In an Earth-scale world model, 3DEP is not a replacement for a broader place and feature inventory; it is an elevation layer that helps explain the physical context around other geographic objects. Its rasters and point clouds support operations such as extracting elevation along roads, measuring building or infrastructure exposure, ranking sites by slope, identifying drainage paths, comparing terrain across regions, and detecting potential topographic constraints. The connection is strongest when elevation is joined to other location data and used for geographic measurement rather than viewed as a standalone map background.
- •Join 3DEP elevation surfaces to roads, buildings, waterways, utility assets, or public facilities to calculate elevation, slope, relief, drainage context, or terrain-based accessibility for each feature.
- •Use LiDAR-derived terrain and surface measurements to rank candidate sites, compare neighborhoods or watersheds, filter features by elevation or slope, and aggregate physical-world characteristics across geographic regions.
- •Combine dated 3DEP source projects with other imagery or infrastructure data to investigate terrain change, flood exposure, construction context, or inconsistencies between mapped features and the observed surface.
Dataset profile
Formats
LAZ compressed LiDAR point clouds
LAS-compatible point-cloud structures and attributes
GeoTIFF
Cloud Optimized GeoTIFF
IMG, BIL, and other product-specific or legacy raster formats
XML textual metadata
GeoPackage spatial metadata
Access methods
The National Map Viewer and Download Platform
USGS LidarExplorer
USGS EarthExplorer
USGS ScienceBase and Science Data Catalog
The National Map web services
Elevation Point Query Service
Bulk Point Query Service
Quality and limits
Resolution does not by itself determine vertical or horizontal accuracy.
Acquisition dates, source sensors, point densities, terrain conditions, classification quality, and processing histories vary by project.
Vegetation, water, snow, flooding, steep terrain, structures, and ground-detection problems can affect elevation interpretation.
Seamless mosaics may combine source data from different dates and projects.
Vertical datum, horizontal coordinate reference system, units, and geoid transformations must be checked before combining products.
3DEP is not a real-time terrain-monitoring service, legal survey, parcel boundary source, or automatic substitute for locally authoritative engineering data.
Analysis workflows
Select the product based on the physical question: point cloud, bare-earth DEM, surface model, seamless DEM, or elevation query.
Inspect acquisition date, resolution, quality level, vertical datum, horizontal CRS, source project, metadata, and NoData conventions.
Mosaic or stream raster tiles only after validating alignment, units, coordinate systems, and vertical references.
For LiDAR, filter by return and classification, inspect point density, and validate ground or surface classifications before deriving measurements.
Derive slope, aspect, hillshade, contours, relief, flow direction, accumulation, and watershed boundaries with documented processing choices.
Sample elevation or terrain derivatives at points, along lines, or within polygons representing roads, buildings, waterways, infrastructure, and public assets.
Compare source dates and quality records when using 3DEP for change detection or exposure analysis.
Preserve product identifiers, source metadata, transformation steps, and uncertainty notes alongside derived geographic results.
Value inside EDK
What USGS 3DEP contains
The 3D Elevation Program provides elevation information through several related product families. The most detailed source data is the LiDAR point cloud: three-dimensional points with x, y, and z coordinates plus attributes such as return information, intensity, classification, and point-source metadata. Classified point clouds can be filtered to ground returns, vegetation, buildings, water, bridges, or other classes when those classifications are available and appropriate for the project.
3DEP also distributes derived digital elevation models. A bare-earth DEM attempts to represent the terrain after vegetation and structures have been removed, while a digital surface model represents the upper surface and can include trees, buildings, and other objects. The distinction matters for flood modeling, road grades, watershed analysis, line-of-sight work, and building or canopy studies. Alaska also has 5-meter IfSAR-derived products, including digital surface and terrain models, distributed as GeoTIFF through USGS systems. (usgs.gov)
- •LiDAR point clouds: detailed three-dimensional observations, commonly classified and distributed by project or tile.
- •Original Product Resolution and project DEMs: elevation surfaces derived from specific source acquisitions.
- •Seamless DEMs: mosaicked or blended products intended for continuous regional or national analysis.
- •Alaska IfSAR: radar-derived digital surface and terrain products at approximately 5-meter spacing.
- •Metadata and spatial source records: information about source projects, processing, quality, and geographic extent.
Geography, temporal coverage, and update cadence
3DEP is primarily a United States elevation program, covering the conterminous United States, Alaska, Hawaii, U.S. territories, and selected adjacent areas depending on the product. The 1/3-arc-second seamless DEM provides coverage across the 48 contiguous states, Alaska, Hawaii, and U.S. territories. The 1-arc-second product also covers the conterminous United States and Alaska, with much of Canada and Mexico present in the broader elevation surface. Product-specific availability must be checked for the exact area of interest. (usgs.gov)
There is no single national refresh interval for every 3DEP file. The downloadable holdings include source data beginning in 2004 and continuing to the present, but acquisition dates differ across projects and places. A local LiDAR tile may represent a particular flight campaign, while a seamless DEM may combine source projects from different dates. The USGS says production of the 1-meter seamless DEM began in mid-2025 and that new 10-kilometer tiles are added as they become available. (usgs.gov)
- •Geographic scope: United States-focused, with product-specific coverage differences.
- •Temporal coverage: source holdings extend from 2004 to the present, with varying local acquisition dates.
- •Update cadence: irregular and project-driven for source LiDAR; expanding production for the 1-meter seamless DEM.
- •Best practice: preserve acquisition date, publication date, source project, and processing lineage in every analysis.
Download options, formats, and access methods
The National Map Viewer and Download Platform is the primary browser-based method for selecting an area and downloading 3DEP products. Users can also use LidarExplorer for LiDAR point clouds and DEMs, EarthExplorer for selected USGS holdings including Alaska IfSAR, and USGS ScienceBase or the USGS Science Data Catalog for product records and metadata. The USGS also provides elevation query services for retrieving a ground elevation at a coordinate and bulk point-query services for multiple longitude-latitude pairs. (usgs.gov)
LiDAR point clouds are distributed as LAZ, a lossless compressed representation of the ASPRS LAS format. LAZ is much smaller than uncompressed LAS while preserving the point information needed for processing. Current 3DEP lidar production requirements reference LAS 1.4-R15 and point data record formats, while the downloadable distribution commonly uses LAZ for efficiency. (data.usgs.gov)
- •Browser download: The National Map Downloader and LidarExplorer.
- •Catalog and bulk discovery: USGS ScienceBase, Science Data Catalog, Data.gov, and EarthExplorer where applicable.
- •Point queries: Elevation Point Query Service and bulk point-query service.
- •Point-cloud format: LAZ, with LAS-compatible structure and attributes.
- •Raster formats: GeoTIFF and Cloud Optimized GeoTIFF, with some legacy or product-specific alternatives.
- •Metadata: XML product records and spatial metadata in GeoPackage form.
Suitable GIS and spatial-analysis workflows
For terrain mapping, start with a DEM whose resolution and source are appropriate to the question. Mosaic tiles only after checking that the coordinate reference systems, vertical datums, units, pixel alignment, and NoData rules are compatible. Derive slope, aspect, hillshade, curvature, local relief, flow direction, and flow accumulation in a projected coordinate system suitable for the area. Resampling should be documented because it changes the effective representation of terrain.
For hydrology, use a bare-earth surface and inspect sinks, bridges, culverts, hydroflattening, breaklines, and known voids before deriving streams or watersheds. A DEM that is visually smooth may still contain artifacts that affect flow routing. USGS specifications for elevation-derived hydrography emphasize the use of suitable 3DEP source data, seamless project-area coverage, metadata, and attention to source quality and terrain conditions. (usgs.gov)
- •Terrain visualization: hillshade, contours, relief, 3D scenes, and profiles.
- •Hydrology: watershed delineation, drainage modeling, flood-context analysis, and stream extraction with validation.
- •Infrastructure: road-grade measurement, site screening, corridor analysis, and engineering pre-analysis.
- •Urban and environmental analysis: building context, canopy or surface structure, erosion, habitat, and exposure studies.
- •Geographic computation: zonal statistics, point sampling, line profiling, proximity analysis, ranking, and regional aggregation.
Limitations, interpretation, and tradeoffs
3DEP is authoritative in the sense of being a USGS-managed national elevation program, but it is not uniformly current or uniformly detailed. Source projects differ in collection date, sensor, point density, terrain, vegetation, weather, vertical accuracy, classification, and processing history. A seamless product improves continuity and usability, but it may be less detailed than the highest-resolution source data available for a local project.
Resolution is not the same as accuracy. A 1-meter cell does not guarantee 1-meter positional or vertical accuracy, and a dense point cloud does not automatically provide reliable ground elevations under dense vegetation, water, snow, or complex structures. Quality levels, accuracy reports, metadata, and source-specific limitations should be reviewed before using the data for design, legal determinations, safety-critical decisions, or regulatory work. The current 3DEP collection requirements specify minimum standards for new collections, but existing holdings can include approved variances and legacy products. (usgs.gov)
- •Strengths: national scope, authoritative federal stewardship, open public-domain access, rich LiDAR and DEM product family.
- •Strengths: multiple resolutions and representations, from point clouds to seamless rasters and coordinate queries.
- •Strengths: extensive metadata, documented specifications, and compatibility with mainstream GIS and remote-sensing workflows.
- •Tradeoff: acquisition dates and update timing vary substantially by location and product.
- •Tradeoff: high-resolution LiDAR can be large, computationally demanding, and difficult to process on limited hardware.
- •Tradeoff: elevation accuracy, classification quality, vertical datum, and surface interpretation require product-level inspection.
- •Tradeoff: a seamless DEM may hide source-project differences or provide less detail than local original-resolution products.
Questions teams ask
Is USGS 3DEP one dataset or several datasets?
It is a family of related elevation products and services. The ecosystem includes LiDAR point clouds, project-level DEMs, seamless DEMs at multiple resolutions, Alaska IfSAR products, metadata, and elevation-query services. The correct download depends on whether the workflow needs individual three-dimensional observations, a bare-earth terrain surface, a surface model, or a generalized seamless elevation layer.
What format should I download for GIS?
For raster elevation analysis, GeoTIFF or Cloud Optimized GeoTIFF is usually the most convenient choice when available. For detailed LiDAR processing, LAZ is the standard compressed distribution format and retains the information represented by LAS. Check the product record for coordinate reference system, vertical datum, units, classification conventions, NoData values, and metadata before importing the files.
How current is 3DEP elevation data?
There is no single answer for the entire program. USGS holdings include data collected from 2004 to the present, but the date varies by project and location. The 1-meter seamless DEM is being produced incrementally, with new tiles added as they become available. For currentness, inspect the acquisition and publication dates for the exact tile or project rather than relying only on the 3DEP program name.
What is the difference between a DEM and a LiDAR point cloud?
A LiDAR point cloud contains many individual three-dimensional observations and may include multiple returns and classifications. A DEM is a gridded raster surface derived from source measurements, often intended to represent bare-earth terrain. A digital surface model can include vegetation and structures. Point clouds preserve more source detail but require more processing; DEMs are easier to map, model, and summarize.
Can 3DEP be used for flood, slope, or watershed analysis?
Yes, 3DEP is widely suited to terrain and hydrologic workflows, but the product must be selected and validated carefully. Use a suitable bare-earth surface, inspect the acquisition conditions and vertical reference, review hydroflattening and breakline information where available, and validate derived drainage or flood-related results against local data and the requirements of the specific decision.
Keep exploring
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Sources
About 3DEP Products & Services
Official USGS overview of 3DEP product families, resolutions, coverage, formats, and the 1-meter seamless DEM.
Open sourceGIS Data Download
Official USGS description of National Map download methods, LidarExplorer, EarthExplorer, and elevation services.
Open sourceLidar Point Cloud — USGS National Map 3DEP Downloadable Data Collection
Official USGS catalog record describing 3DEP LiDAR point clouds, LAZ, temporal coverage, and public-domain status.
Open source3DEP Product Metadata
Official USGS documentation for XML textual metadata and GeoPackage spatial metadata.
Open sourceLidar Base Specification: Collection Requirements
Official USGS specification for minimum collection requirements, quality levels, point density, returns, and data-void rules.
Open sourceNew Product from the 3D Elevation Program: Seamless 1 Meter Digital Elevation Model
Official USGS explanation of the seamless 1-meter DEM and its intended analysis applications.
Open source