There are a variety of resources available via The National Map homepage, such as static maps, interactive map viewers, and geospatial data. Some of these maps and apps include, the National Map Viewer, the 3D Elevation Program, the National Hydrography Dataset and Hydrography Viewer, the Historical Topographic Map and the US Topo. Via The National Map, historical topographic maps are available to search and download via a variety of options. The 3D Elevation Program (3DEP) provides information about, and access to elevation data meeting the 3DEP guidelines. Users can also access and view the National Hydrography Dataset via the Hydrography viewer; this is similar to the National Map Viewer, however the basemap is based on HUC watersheds. Using the National Map Viewer, users can search for, access and download current 7.5 minute US Topos for the entire country; users can also explore and view other data for their area of interest. Below, find links to the different The National Map resources that were described above. The National Map also provides access to other data and viewers, such as the National Land Cover Database, and The National Map Corps.

The USGS Elevation Contours service from The National Map (TNM) consists of contours generated for the conterminous United States from 1- and 1/3 arc-second elevation data. Small scale contours derived from 1 arc-second data are displayed at scales ranging from 1:577K to 1:72K in The National Map viewer. Contour intervals are 100 foot between 1:577K and 1:144K, and 50 foot at 1:72K. Large scale contours derived from 1/3 arc-second data are displayed at 1:50K (and larger). Large scale contour intervals are variable across the United States depending on complexity of topography. The National Map viewer allows free downloads of public domain contour data in either Esri File Geodatabase or Shapefile formats. The 3D Elevation Program (3DEP) provides elevation data for The National Map and basic elevation information for earth science studies and mapping applications. Scientists and resource managers use elevation data for global change research, hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. For additional information on 3DEP, go to http://nationalmap.gov/3DEP/.

The ArcGIS Online USGS Topographic Maps image service contains over 181,000 historical topographic quadrangle maps (quads) dating from 1879 to 2006. These maps are part of the USGS Historical Topographic Map Collection (HTMC) which includes all the historical quads that had been printed since the USGS topographic mapping program was initiated in 1879. Previously available only as printed lithographic copies, the historical maps were scanned “as is” to create high-resolution images that capture the content and condition of each map sheet. All maps were georeferenced, and map metadata was captured as part of the process.

For the Esri collection, the scanned maps were published as this ArcGIS Online image service which can be viewed on the web and allows users to download individual scanned images. Esri’s collection contains historical quads (excluding orthophotos) dating from 1879 to 2006 with scales ranging from 1:10,000 to 1:250,000. The scanned maps can be used in ArcGIS Pro, ArcGIS Online, and ArcGIS Enterprise. They can also be downloaded as georeferenced TIFs for use in these and other applications.

We make it easy for you to explore and download these maps, or quickly create an ArcGIS Online map, using our Historical Topo Map Explorer app. The app provides a visual interface to search and explore the historical maps by geographic extent, publication year, and map scale. And you can overlay the historical maps on a satellite image or 3D hillshade and add labels for current geographic features.

This is a tiled collection of the 3D Elevation Program (3DEP) and is 1 arc-second (approximately 30 m) resolution. The elevations in this Digital Elevation Model (DEM) represent the topographic bare-earth surface. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications.. The seamless 1 arc-second DEM layers are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the continental United States, are referenced to the North American Vertical Datum of 1988 (NAVD88). The seamless 1 arc-second DEM layer provides coverage of the conterminous United States, Hawaii, Puerto Rico, other territorial islands, and much of Alaska and Canada. The seamless 1 arc-second DEM is available as pre-staged products tiled in 1 degree blocks in Erdas .img, ESRI arc-grid, and grid float formats. The seamless 1 arc-second DEM layer is updated continually as new data become available. Other 3DEP products are nationally seamless DEMs in resolutions of 1 and 1/3 arc-second. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. Other 3DEP products include one-meter DEMs produced exclusively from high resolution light detection and ranging (lidar) source data and five-meter DEMs in Alaska as well as various source datasets including the lidar point cloud and interferometric synthetic aperture radar (Ifsar) digital surface models and intensity images. All 3DEP products are public domain.

December 1995, June 2001

This is a tiled collection of the 3D Elevation Program (3DEP) and is one meter resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. USGS standard one-meter DEMs are produced exclusively from high resolution light detection and ranging (lidar) source data of one-meter or higher resolution. One-meter DEM surfaces are seamless within collection projects, but, not necessarily seamless across projects. The spatial reference used for tiles of the one-meter DEM within the conterminous United States (CONUS) is Universal Transverse Mercator (UTM) in units of meters, and in conformance with the North American Datum of 1983 (NAD83). All bare earth elevation values are in meters and are referenced to the North American Vertical Datum of 1988 (NAVD88). Each tile is distributed in the UTM Zone in which it lies. If a tile crosses two UTM zones, it is delivered in both zones. The one-meter DEM is the highest resolution standard DEM offered in the 3DEP product suite. Other 3DEP products are nationally seamless DEMs in resolutions of 1/3, 1, and 2 arc seconds. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. Other 3DEP products include five-meter DEMs in Alaska as well as various source datasets including the lidar point cloud and interferometric synthetic aperture radar (Ifsar) digital surface models and intensity images. All 3DEP products are public domain.

Shared Enterprise Geodata and Services (SEGS) provides an EPA-curated collection of recommended geodata assets that are nationally relevant and support the Agency’s mission to protect human health and the environment. By connecting EPA users with curated datasets and promoting service reuse, SEGS aims to enhance information access, reduce data-storage costs, and improve the consistency and quality of data at the US EPA. The 3D Elevation Program is managed by the U.S. Geological Survey (USGS) National Geospatial Program to respond to growing needs for high-quality topographic data and for a wide range of other three-dimensional (3D) representations of the Nation's natural and constructed features. 3DEP informs critical decisions that are made across our Nation every day that depend on elevation data, ranging from immediate safety of life, property, and environment to long term planning for infrastructure projects.3DEP is based on the results of the National Enhanced Elevation Assessment (NEEA) that was funded by National Digital Elevation Program (NDEP) agencies and completed in 2011. The study, led by the USGS, identified more than 600 requirements for enhanced (3D) elevation data to address mission-critical information requirements of 34 Federal agencies, all 50 States, and a sample of private sector companies and Tribal and local governments. The USGS Elevation Contours service from The National Map displays contours generated for the United States at various scales. Small-scale contours were created by USGS TNM from 1 arc-second data with 100-meter contours, and are visible at 1:600,000 and smaller scales. Medium-scale contours were created by USGS EROS from 1/3-arc-second data with 100-foot intervals, and are visible between 1:150,000 and 1:600,000. Additional medium-scale contours were created by USGS EROS from 1/3-arc-second data with 50-foot intervals, and are visible between 1:50,000 and 1:150,000. Large scale contours are updated every quarter, and are created by USGS TNM for the 7.5' 1:24,000-scale US Topo digital map series. These contours are derived from 1/3 arc-second or better resolution data, and are visible at scales 1:50,000 and larger. Large scale contour intervals are variable across the United States depending on complexity of topography, and as contours are generated per US Topo quadrangle, lines may not match across quad boundaries.

10-foot elevation contours for the extent of the state of Indiana, created from downloading, projecting and combining several datasets from USGS based on 7.5-minute quadrangle boundaries. These vector contour lines are derived from the 3D Elevation Program using automated and semi-automated processes. They were created to support 1:24,000-scale CONUS and Hawaii, 1:25,000-scale Alaska, and 1:20,000-scale Puerto Rico / US Virgin Island topographic map products, but are also published in this GIS vector format. Contour intervals are assigned by 7.5-minute quadrangle, so this vector dataset is not visually seamless across quadrangle boundaries. The vector lines have elevation attributes (in feet above mean sea level on NAVD88), but this dataset does not carry line symbols or annotation. Description from the original source metadata: These vector contour lines are derived from the 3D Elevation Program using automated and semi-automated processes. They were created to support 1:24,000-scale CONUS and Hawaii, 1:25,000-scale Alaska, and 1:20,000-scale Puerto Rico / US Virgin Island topographic map products, but are also published in this GIS vector format. Contour intervals are assigned by 7.5-minute quadrangle, so this vector dataset is not visually seamless across quadrangle boundaries. The vector lines have elevation attributes (in feet above mean sea level on NAVD88), but this dataset does not carry line symbols or annotation.Source files downloaded from The National Map on 11/18/2019:https://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Muncie_W_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Danville_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Vincennes_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Louisville_W_KY_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Cincinnati_W_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Indianapolis_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Fort_Wayne_W_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Chicago_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Indianapolis_W_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Danville_W_IL_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Vincennes_W_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Chicago_W_IL_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Cincinnati_E_OH_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Muncie_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Louisville_E_KY_1X1_GDB.zip https://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Fort_Wayne_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Evansville_E_IN_1X1_GDB.ziphttps://prd-tnm.s3.amazonaws.com/StagedProducts/Contours/GDB/ELEV_Evansville_W_IN_1X1_GDB.zip

U.S. Geological Survey, Department of the Interior - The annual Alaska IfSAR and DEM acquisition plan is part of the 3DEP initiative to collect high-quality elevation data in the form of interferometric synthetic aperture radar (IfSAR) and light detection and ranging (lidar) data over Alaska. This acquisition plan addresses concerns raised in GAO Report 13-94 regarding geospatial coordination, and supports FGDC data coordination initiatives led by the Department of Interior's Geospatial Information Officer. Mapping a State the size and complexity of Alaska through a partnered effort such as the Alaska Mapping Initiative requires dedicated collaboration and coordination across multiple levels of government. State efforts for the collection of IfSAR data are being coordinated through Alaska's Statewide Digital Mapping Initiative (SDMI), a cooperative program implemented across six State of Alaska departments and the University of Alaska. Federal efforts are coordinated through the Alaska Mapping Executive Committee (AMEC), chaired by the Department of the Interior with membership from 15 Federal agencies and representatives from the State of Alaska (Charter can be found at http://nationalmap.gov/alaska/amec_charter.html ). The FY19 acquisition plan currently anticipates collecting 16,000 sq. mi. or more depending on partnerships and other contributions to the plan. Interested parties who wish to become a funding partner with the USGS in FY19 or in future years should contact Becci Anderson, USGS Geospatial Liaison, rdanderson@usgs.gov. Products will include: 5M DEM/DSM, Orthorectified IfSAR Intensity Image (ORII), and other standard derived 3DEP datasets. To find out more about the Alaska IfSAR Acquisition for 3DEP initiative go to http://nationalmap.gov/alaska/ami_partners.html

This is a tiled collection of images with 1m pixel size from the 3D Elevation Program (3DEP). The 3DEP data holdings serve as the elevation layer of The National Map and provide foundational elevation information for earth science studies and mapping applications in the United States. The elevations in this DEM represent the topographic bare-earth surface. USGS standard 1m pixel size DEMs are produced exclusively from high resolution light detection and ranging (lidar) source data of images with 1m pixel size or higher resolution. 1m pixel size DEM surfaces are seamless within collection projects but not necessarily seamless across projects. The spatial reference used for tiles of the 1m pixel size DEM within the conterminous United States (CONUS) is Universal Transverse Mercator (UTM) in units of meters and in conformance with the North American Datum of 1983 (NAD83). All bare earth elevation values are in meters and are referenced to the North American Vertical Datum of 1988 (NAVD88). Each tile is distributed in the UTM Zone in which it lies. If a tile crosses two UTM zones, it is delivered in both zones. In this and other cases of image overlaps, elevation values might be slightly different in different images covering the same area. The 1m pixel size DEM is the highest resolution standard DEM offered in the 3DEP product suite. The 10m 3DEP dataset is available at USGS_3DEP_10m.

Link to the ScienceBase Item Summary page for the item described by this metadata record. Service Protocol: Link to the ScienceBase Item Summary page for the item described by this metadata record. Application Profile: Web Browser. Link Function: information

This is a 1 arc-second (approximately 30 m) resolution tiled collection of the 3D Elevation Program (3DEP) seamless data products . 3DEP data serve as the elevation layer of The National Map, and provide basic elevation information for Earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for global change research, hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. 3DEP data compose an elevation dataset that consists of seamless layers and a high resolution layer. Each of these layers consists of the best available raster elevation data of the conterminous United States, Alaska, Hawaii, territorial islands, Mexico and Canada. 3DEP data are updated continually as new data become available. Seamless 3DEP data are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the conterminous United States, are referenced to the North American Vertical Datum of 1988 (NAVD 88). The vertical reference will vary in other areas. The elevations in these DEMs represent the topographic bare-earth surface. All 3DEP products are public domain. This dataset includes data over Canada and Mexico as part of an international, interagency collaboration with the Mexico's National Institute of Statistics and Geography (INEGI) and the Natural Resources Canada (NRCAN) Centre for Topographic Information-Sherbrook, Ottawa. For more details on the data provenance of this dataset, visit here and here. Click here for a broad overview of this dataset

The USGS 3D Hydrography Program (3DHP) ArcGIS REST service (3DHP_all) from The National Map is the first of several data services that will be delivered by the 3D Hydrography Program. The 3DHP_all comprises a national network of flowlines, hydrolocations, and water bodies, and will include catchments, drainage areas, and flow network derivatives as they are populated in the future. The 3DHP_all service will provide access to a 3D-enabled geospatial hydrography vector dataset built from 3DHP data and intended to provide the most comprehensive but general rendering of 3DHP data. 3DHP data is derived from elevation-derived hydrography (EDH) Elevation-Derived Hydrography Specifications | U.S. Geological Survey (usgs.gov) where available. Where EDH has not been collected, 3DHP data will be supplemented by data from the National Hydrography Dataset (NHD) National Hydrography Dataset | U.S. Geological Survey (usgs.gov). As further EDH data is collected, the EDH data will replace the NHD data in that data collection area. 3DHP data ingested from EDH sources will include catchments, drainage areas derived from catchments, and flowline network attribute derivatives.Use Constraints: _ None. All data are open and non-proprietary. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of this data may no longer represent actual conditions. Users should not use this data for critical applications without a full awareness of its limitations. This dataset is not intended to be used for site-specific regulatory determinations. Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from these data.For additional information on the 3DHP, go to https://www.usgs.gov/3dhp.See https://apps.nationalmap.gov/help/ for assistance with The National Map viewer, download client, services, or metadata.

The USGS Elevation Contours service from The National Map (TNM) consists of contours generated for the conterminous United States from 1- and 1/3 arc-second elevation data. Small scale contours derived from 1 arc-second data are displayed at scales ranging from 1:577K to 1:72K in The National Map viewer. Contour intervals are 100 foot between 1:577K and 1:144K, and 50 foot at 1:72K. Large scale contours derived from 1/3 arc-second data are displayed at 1:50K (and larger). Large scale contour intervals are variable across the United States depending on complexity of topography. The National Map viewer allows free downloads of public domain contour data in either Esri File Geodatabase or Shapefile formats. The 3D Elevation Program (3DEP) provides elevation data for The National Map and basic elevation information for earth science studies and mapping applications. Scientists and resource managers use elevation data for global change research, hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. For additional information on 3DEP, go to http://nationalmap.gov/3DEP/.

This layer of the National Elevation Dataset (NED) is 1/9 arc-second (approximately 3 m) resolution. The 1/9 arc-second NED are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the continental United States, are referenced to the North American Vertical Datum of 1988 (NAVD88). The 1/9 arc-second NED layer provides project-based coverage for portions of the conterminous United States, limited areas of Alaska, and Guam. The 1/9 arc-second NED layer is available as pre-staged products tiled in 15 minute blocks in Erdas .img format. The NED is updated continually as new data become available. For a quick reference to visualize where data exists for this collection see: http://viewer.nationalmap.gov/viewer/?p=ned. All NED data are in the public domain.

The USGS 3D Elevation Program (3DEP) Index service from The National Map shows two general categories of downloadable elevation data: (1) digital elevation model (DEM) datasets at standardized horizontal resolutions, and (2) elevation source data including that used to produce standard DEMs, and additional datasets derived from ifsar in Alaska only. Distributable DEM products include: 2 arc-second (in Alaska only); 1 arc-second; 1/3 arc-second; 1/9 arc-second; 5 meter (in Alaska only); and 1 meter. The 2-, 1-, and 1/3-arc-second products are staged for download in 1x1 degree tiles in ArcGrid, GridFloat, or IMG formats, while 1/9 arc-second products are staged in 15x15 minute tiles in IMG format only. The 5-meter products are staged for download in ArcGrid only as a single mosaicked raster to each project extent. The 1-meter products are staged in 10,000x10,000 meter tiles in IMG format only. Distributable elevation source data include: lidar point clouds (LPC) in LAS format for various parts of the U.S., and ifsar-derived digital surface models (DSM) and orthorectified radar images (ORI) in TIFF format in Alaska only. For additional information on the 3DEP, go to http://nationalmap.gov/3DEP/index.html.

This collection of the 3D Elevation Program (3DEP) is at 1/3 arc-second (approximately 10 m) resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. The seamless 1/3 arc-second DEM layers are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the continental United States, are referenced to the North American Vertical Datum of 1988 (NAVD88). The vertical reference will vary in other areas. The seamless 1/3 arc-second DEM layer provides coverage of the conterminous United States, Hawaii, Puerto Rico, other territorial islands, and in limited areas of Alaska. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. All 3DEP products are public domain.

The USGS 3D Elevation Program (3DEP) Bare Earth DEM Dynamic service is based on multi-resolution USGS DEM sources and provides dynamic functions for visualization. These functions include: Hillshade, Aspect Map, Hillshade Stretched, Multi-directional Hillshade, Slope Map, Elevation Tinted Hillshade, Contour. In addition the OGC Web Map Service (WMS) and Web Coverage Service (WCS) interfaces are enabled.

This is a tiled collection of the 3D Elevation Program (3DEP) and is 1/9 arc-second (approximately 3 m) resolution.The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. The seamless 1/9 arc-second DEM layers are derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. These data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the continental United States, are referenced to the North American Vertical Datum of 1988 (NAVD88). The seamless 1/9 arc-second DEM layer project-based coverage for portions of the conterminous United States, limited areas of Alaska, and Guam. The seamless 1/9 arc-second NED layer is available as pre-staged products tiled in 15 minute blocks in Erdas .img format. Since 2015, the seamless 1/9 arc-second DEM layer is no longer being updated. Other 3DEP products are nationally seamless DEMs in resolutions of 1/3, 1, and 2 arc seconds. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. Other 3DEP products include one-meter DEMs produced exclusively from high resolution light detection and ranging (lidar) source data and five-meter DEMs in Alaska as well as various source datasets including the lidar point cloud and interferometric synthetic aperture radar (Ifsar) digital surface models and intensity images. All 3DEP products are public _domain.

This is a tiled collection of the 3D Elevation Program (3DEP) covering Alaska only, and is 5-meter resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. USGS standard 5-meter DEMs are produced exclusively from interferometric synthetic aperture radar (Ifsar) source data of 5-meter or higher resolution. Five-meter DEM surfaces are seamless within collection projects, but, not necessarily seamless across projects. This DEM is delivered in the original resolution, with the original spatial reference. All elevation units have been converted to meters. These data may be used as the source of updates to the seamless 1/3 arc-second DEM layer, which serves as the elevation layer of The National Map. Other 3DEP products are nationally seamless DEMs in resolutions of 1 and 2 arc seconds. These seamless DEMs were referred to as the National Elevation Dataset (NED) from about 2000 through 2015 at which time they became the seamless DEM layers under the 3DEP program and the NED name and system were retired. Other 3DEP products in Alaska include lidar point cloud and interferometric synthetic aperture radar (Ifsar) digital surface models and intensity images. All 3DEP products are public domain.