Are 3D Elevation Program (3DEP) contour lines updated and what sources were used to create them?
When significant changes in the landscape have occurred, contours will be updated on an as-needed basis.
The 100-foot contours were derived from 3DEP (formerly National Elevation Dataset) one arc-second resolution data that was sub-sampled to a cell size of three arc-second. The 50-foot contours were also derived from one arc-second data. Large-scale contours were derived from 1/3 arc-second resolution data for US Topo products.
The seamless digital elevation models (DEMs) used to create the contour lines are enhanced as we collect lidar over the US through the 3DEP program.
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How do I find, download, or order topographic maps? How do I find, download, or order topographic maps?
The U.S. Geological Survey (USGS) has been the primary civilian mapping agency of the United States since 1879. Some of the most well-known USGS maps are the 1:24,000-scale topographic maps, also called 7.5-minute quadrangles. In 2009, the USGS transitioned from our hand scribed historical topographic maps to US Topos, which are computer-generated on a regular schedule using national databases...
What types of elevation datasets are available, what formats do they come in, and where can I download them? What types of elevation datasets are available, what formats do they come in, and where can I download them?
Digital elevation data for the United States and its territories are available through The National Map Downloader. Click the “Help” link at the top of the page for detailed instructions on how to find and download data. There's a separate site for The National Map Services. Downloads and map services are free; no account is required. The 3D Elevation Program (3DEP) products and services available...
Related
How do I find, download, or order topographic maps? How do I find, download, or order topographic maps?
The U.S. Geological Survey (USGS) has been the primary civilian mapping agency of the United States since 1879. Some of the most well-known USGS maps are the 1:24,000-scale topographic maps, also called 7.5-minute quadrangles. In 2009, the USGS transitioned from our hand scribed historical topographic maps to US Topos, which are computer-generated on a regular schedule using national databases...
What types of elevation datasets are available, what formats do they come in, and where can I download them? What types of elevation datasets are available, what formats do they come in, and where can I download them?
Digital elevation data for the United States and its territories are available through The National Map Downloader. Click the “Help” link at the top of the page for detailed instructions on how to find and download data. There's a separate site for The National Map Services. Downloads and map services are free; no account is required. The 3D Elevation Program (3DEP) products and services available...