USGS 3DEP: 1/9th Arc-Second Digital Elevation Models for North America

The United States Geological Survey's 3D Elevation Program (3DEP) provides a tiled collection of bare-earth topographic data covering the conterminous United States, Hawaii, Puerto Rico, other territorial islands, and much of Alaska and Canada. The seamless 1/9th arc-second (approximately 30-meter) resolution DEMs are derived from diverse source data, processed to a common coordinate system (NAD 83) and vertical datum (NAVD 88), with all elevation values in meters. This collection serves as the foundational elevation layer for The National Map and is updated continually as new data become available.

Use Cases

• Hydrologic modeling and watershed analysis based on topographic surface data.
• Resource monitoring and landscape change detection based on foundational elevation information.
• Geospatial mapping and visualization for scientific studies based on the seamless DEM layer.
• Terrain analysis for engineering and planning based on the 30-meter resolution bare-earth model.

Strengths

• Data is processed to a common coordinate system (NAD 83) and vertical unit (meters).
• Coverage includes the conterminous U.S., Hawaii, Puerto Rico, and parts of Alaska and Canada.
• The dataset is updated continually as new source data become available.
• Elevations represent the topographic bare-earth surface, filtered of vegetation and structures.

Limitations

• Row count and total file size are unknown, which may limit suitability assessment.
• Column-level documentation is absent; field semantics must be inferred after download.
• The description does not specify the exact temporal coverage for the data tiles.

Provenance

Source

United States Geological Survey (USGS) 3D Elevation Program (3DEP).

Collection Method

Derived from diverse source data (e.g., LiDAR, IfSAR) processed to a common standard.

Freshness

Updated continually; last update date is unknown.

Geography

Conterminous United States, Hawaii, Puerto Rico, other U.S. territorial islands, and much of Alaska and Canada.