2025 USGS Lidar DEM: Los Angeles Post-Wildfire, CA

Original Product: These are Digital Elevation Model (DEM) data for California as part of the required deliverables for the CA_LAPostWildfire project. Class 2 (ground) LiDAR points in conjunction with the hydro breaklines were used to create a 0.5 meter hydro-flattened Raster DEM.

Original Geographic Extent:

CA_LAPostWildfire_Eaton (Work Unit 300866) - Los Angeles County in California, covering approximately 60 total square miles.

CA_LAPostWildfire_Palisades (Work Unit 300865) - Los Angeles County in California, covering approximately 104 total square miles.

Original Dataset Description: The CA_LAPostWildfire project called for the planning, acquisition, processing, and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.25 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LiDAR Specification, 2024 Rev. A. The data were developed based on a horizontal projection/datum of NAD 1983 2011 UTM Zone 11N, Meter and vertical datum of NAVD88 Geoid 18, Meter. LiDAR data were delivered as processed Classified LAS 1.4 files formatted to individual 750 m x 750 m tiles, as tiled intensity imagery, and as tiled bare earth DEMs; all tiled to the same 750 m x 750 m schema. Continuous breaklines were produced in Esri file geodatabase format.

Original Ground Conditions:

CA_LAPostWildfire_Eaton (Work Unit 300866)

LiDAR was collected in winter 2025, while no snow was on the ground and rivers were at or below normal levels. In order to post process the LiDAR data to meet task order specifications and meet ASPRS vertical accuracy guidelines, NV5 Geospatial utilized a total of 4 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 28 independent accuracy checkpoints, 16 in Bare Earth and Urban landcovers (16 NVA points), 12 in Tall Weeds categories (12 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

CA_LAPostWildfire_Palisades (Work Unit 300865)

LiDAR was collected in winter 2025, while no snow was on the ground and rivers were at or below normal levels. In order to post process the LiDAR data to meet task order specifications and meet ASPRS vertical accuracy guidelines, NV5 Geospatial utilized a total of 9 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 39 independent accuracy checkpoints, 22 in Bare Earth and Urban landcovers (22 NVA points), 17 in Tall Weeds categories (17 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the GeoTIFF files hosted by USGS on Amazon Web Services.

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create intensity images, breaklines and raster DEMs. The purpose of these LiDAR data was to produce high accuracy 3D hydro-flattened digital elevation models (DEMs) with a 0.5 meter cell size. These raw LiDAR point cloud data were used to create classified LiDAR LAS files, intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Raster File Type = GeoTIFF; Bit Depth/Pixel Type = 32-bit float; Raster Cell Size = 0.5 meter; Interpolation or Resampling Technique = Triangulated Irregular Network (TIN), Linear Interpolation, Proprietary; Required Vertical Accuracy = 0.196

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

CA_LAPostWildfire_Eaton (Work Unit 300866)

CA_LAPostWildfire_Palisades (Work Unit 300865)

To the extent possible under law, the U.S. Government has waived all copyright and related or neighboring rights to this dataset.

Data is available online for bulk and custom downloads.

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional error, flying altitude, and INS derived attitude error. The obtained RMSEr value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within the obtained radius 95% of the time.

CA_LAPostWildfire_Eaton

Based on an RMSEr value of 0.2 meters, a flying altitude of 3,201 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.019 meters, this project was compiled to meet 0.35 meters horizontal accuracy at the 95% confidence level.

CA_LAPostWildfire_Palisades

Based on an RMSEr value of 0.19 meters, a flying altitude of 3,048 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.019 meters, this project was compiled to meet 0.33 meters horizontal accuracy at the 95% confidence level.

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

USGS Determined DEM Vertical Accuracy:

Non-Vegetated Vertical Accuracy (NVA) = 3.67 cm RMSE

Vegetated Vertical Accuracy (VVA) = 29.72 cm at 95th Percentile

Datasets contain complete coverage of tiles. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. There are no void areas or missing data. The raw point cloud is of good quality and data pass Non-Vegetated Vertical Accuracy specifications.

Data cover the entire area specified for this project.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS.