USGS 1 Arc-Second Digital Elevation Model Tiles for Contiguous US

A tiled collection of 1 arc-second (approximately 30-meter) resolution bare-earth elevation data from the USGS 3D Elevation Program. It provides foundational topographic information for the conterminous United States, Hawaii, Puerto Rico, other islands, and parts of Alaska and Canada, referenced to NAD83 and NAVD88 datums. The data is distributed in GeoTIFF format and is updated continually as new source data becomes available.

Use Cases

• Perform hydrologic modeling using the bare-earth elevation values to delineate watersheds and simulate water flow.
• Generate topographic maps and 3D visualizations for resource monitoring and land management applications.
• Conduct earth science studies by analyzing elevation layers for geological feature identification and change detection.
• Support mapping applications by providing a foundational elevation layer for overlaying other geospatial data.

Strengths

• Provides 1 arc-second (approximately 30-meter) resolution elevation data across a broad geographic area.
• Represents the topographic bare-earth surface, processed to common datums (NAD83, NAVD88) and units (meters).
• Data collection is updated continually, with historical versions retained for reproducibility.

Limitations

• Resolution is coarser (30m) compared to other 3DEP products like 1-meter LiDAR-derived DEMs, limiting detail for fine-scale analysis.
• Coverage for Alaska and Canada is described as 'much of', indicating incomplete or patchy data for those regions.
• The primary distribution format listed is XML metadata, requiring users to locate and process the actual GeoTIFF raster files.

Provenance

Source

U.S. Geological Survey's 3D Elevation Program (3DEP).

Collection Method

Derived from diverse source data (e.g., LiDAR, Ifsar) processed to a common coordinate system and vertical measure.

Time Range

Historical and current data available; collection spans from circa 2000 (as NED) through present updates.

Freshness

Updated continually; last metadata update recorded as 2026-01-16.

Geography

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