2022 - 2023 USGS Lidar DEM: WA Central Wildfire

Original Product: These are Digital Elevation Model (DEM) data for Washington as part of the required deliverables for the WA_CentralWildfire project. Class 2 (ground) LiDAR points in conjunction with the hydro breaklines were used to create a 1 foot hydro-flattened Raster DEM.

Original Geographic Extent:

WA_CentralWildfire_1 (Work Unit 300629) - 8 counties in Washington, covering approximately 2537 total square miles. The counties are: Chelan, Douglas, Grant, King, Kittitas, Okanogan, Skagit, Snohomish.

WA_CentralWildfire_2 (Work Unit 300630) - 12 counties in Washington, covering approximately 2958 total square miles. The counties are: Benton, Chelan, Clark, Cowlitz, Douglas, Grant, King, Kittitas, Lewis, Skamania, Thurston, Yakima.

Original Dataset Description: The WA_CentralWildfire project called for the planning, acquisition, processing, and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LiDAR Specification, 2023 Rev. A. The data were developed based on a horizontal projection/datum of NAD 1983 HARN State Plane Washington North and South, Foot US and vertical datum of NAVD88 Geoid 18, Foot US. LiDAR data were delivered as processed Classified LAS 1.4 files formatted to individual 4500 ft x 4500 ft tiles, as tiled intensity imagery, and as tiled bare earth DEMs; all tiled to the same 4500 ft x 4500 ft schema. Continuous breaklines were produced in Esri file geodatabase format.

Original Dataset Ground Conditions: LiDAR was collected in fall 2022 through summer 2023. 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 53 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 114 independent accuracy checkpoints, 62 in Bare Earth and Urban landcovers (62 NVA points), 52 in Tall Weeds categories (52 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 1 foot 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 = 1 foot; 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.

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 or 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.

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 23 (cm) RMSEh Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 41 cm at a 95% confidence level.

The specifications require that only non-vegetated vertical accuracy (NVA) be computed for raw LiDAR data swath files. The vertical accuracy was tested with independent survey points located in open terrain. These check points were not used in the calibration or post processing of the LiDAR data. The survey check points were distributed throughout the project area. This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class. 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) = 6.11 cm RMSE

Vegetated Vertical Accuracy (VVA) = 23.69 cm at the 95th Percentile

Refer to the USGS project report in the URL section of this metadata record.

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.

Data is backed up to cloud storage.

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.