Light Detection and Ranging (lidar) is a technology used to create high-resolution models of ground elevation with a vertical accuracy of 10 centimeters (4 inches).  rnrnFEMA collects lidar elevation data to support flood mapping. USGS is the primary Federal steward of lidar data. FEMA archives lidar data for FEMA projects where USGS does not manage the Lidar data collection. rnrnDatapoints include ground elevation models and vertical metrics for ground elevation.

U.S. Geological Survey (USGS) scientists conducted field data collection efforts between August 17th and 28th, 2020 over a large stretch of the Niobrara River in Nebraska using high accuracy surveying technologies. The work was initiated as an effort to validate commercially acquired topobathymetric light detection and ranging (lidar) data. The goal was to compare and validate the airborne lidar data to topographic, bathymetric, structural, and infrastructural data collected through more traditional means (e.g. Global Navigational Satellite System (GNSS) surveying). The airborne topobathymetric lidar data will be used for characterization of endangered species aquatic habitat, improving the understanding of fluvial geomorphic features, sediment transport modeling, and 2D/3D hydrologic and hydraulic modeling. The impacts of the spring 2019 flood and resulting Spencer Dam failure will be further assessed and monitored using the lidar data along with testing inland topobathymetric lidar mapping capabilities for inclusion in the USGS National Geospatial Program (NGP) 3D Elevation Program (3DEP).

Bare Earth Light Detection and Ranging (LIDAR) Data - 2 foot resolution. The dataset contains locations and attributes of bare earth elevations in meters. Bare earth model is created by identifying those returns that fall on the ground surface and interpolating a surface between these points. In this manner buildings and vegetation are removed from Bare Earth Model. This data set does not include bridges and overpasses in the Bare Earth model as the delineation point for these structures is not reliably discernible in the LiDAR data. This metadata record describes the data products derived from the LiDAR data for the DC OCTO 2015 LiDAR project covering approximately 80 square miles, in which its extents cover Arlington County in Washington DC. This project consists of deliverables in accordance with USGS v1.2 specifications and meets or exceeds the level of quality for QL1 (8 points per meter).

First Return Light Detection and Ranging (LIDAR) Data - 1m resolution. The dataset contains locations and attributes of first return elevations in meters. LIDAR data provided by the Joint Precision Strike Demonstration Project Office of the US Army contained bare earth rasters. This raster contains elevations of all structures, tree canopies, and bare earth.

Intensity Light Detection and Ranging (LIDAR) Data - 1m resolution. Intensity information is captured from the Reflective Surface pulse and indicates the relative energy returned to the sensor as compared to the energy transmitted. The Intensity image is not calibrated or normalized but indicates differences in energy absorption due to the the interaction of the surface materials with laser energy at the wavelength transmitted by the sensor.

These lidar data are processed classified LAS 1.4 files at USGS QL2 covering the District of Columbia. Voids exist in the data due to data redaction conducted under the guidance of the United States Secret Service. This dataset provided as an ArcGIS Image service. Please note, the download feature for this image service in Open Data DC provides a compressed PNG, JPEG or TIFF. The individual LAS point cloud datasets are available under additional options when viewing downloads.