2022 USGS Lidar DEM: Northern California

Original Product: 0.5-meter bare-earth raster digital elevation model (DEM) data tiles in GeoTIFF format.

Original Geographic Extent:

CA_NorthernCA_1 (Work Unit 300326) - 6 counties covering approximately 1603 square miles. The counties are: Lake, Marin, Mendocino, Napa, Solano, Sonoma

CA_NorthernCA_2 (Work Unit 300407) - 2 counties covering approximately 911 square miles. The counties are: Tehama, Shasta

CA_NorthernCA_3 (Work Unit 300464) - 3 counties covering approximately 4241 square miles. The counties are: Lassen, Modoc, Shasta

CA_NorthernCA_4 (Work Unit 300465) - 4 counties covering approximately 2013 square miles. The counties are: Lassen, Modoc, Shasta, Siskiyou

CA_NorthernCA_5 (Work Unit 300466) - 6 counties covering approximately 3382 square miles. The counties are: Del Norte, Humboldt, Shasta, Siskiyou, Tehama, Trinity

CA_NorthernCA_6 (Work Unit 300467) - 7 counties covering approximately 3481 square miles. The counties are: Curry, Del Norte, Humboldt, Jackson, Josephine, Siskiyou, Trinity

CA_NorthernCA_7 (Work Unit 300468) - 5 counties covering approximately 3499 square miles. The counties are: Jackson, Klamath, Lake, Modoc, Siskiyou

Original Dataset Description: This lidar project called for the planning, acquisition, processing, and production of derivative products of QL1 lidar data to be collected an aggregate nominal pulse spacing (ANPS) of 0.35-meters and 8 points per square meter (ppsm). Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2022 revision A. The data was developed based on a horizontal reference system of NAD83 (2011) UTM 10 meters (EPSG 6339) and a vertical reference system of NAVD88 (GEOID18) meters. DEM data was delivered as processed GeoTIFF files formatted to individual 1,000-meters x 1,000-meters tiles.

Ground Conditions: Lidar was collected in 2022 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, Woolpert established ground control points that were used to calibrate the lidar to known ground locations established throughout the entire project area. An additional independent accuracy checkpoints were collected throughout the entire project area and 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.

This project will support the California Natural Resource Agency (CNRA) and North Coast Resource Conservation Partnership (NCRP), Sonoma County Water Agency, University of California - San Diego (UCSD), Humboldt Bay Municipal Water District, Sonoma County Agricultural Preservation and Open Spaces District, United States ForestService GTAC (USFS), National Resources and Conservation Service (NRCS), U.S. Fish and Wildlife Service (USFWS), USGS - Volcano Hazards Program (VHP), USGS - National Geospatial Program (NGP), and the 3DEP mission.

Task Order No. 140G0222F0208, Project Name: CA_NorthernCA_B22. Subcontractor: Woolpert.

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 0.5-meter

Interpolation or Re-sampling Technique = Triangulated Irregular Network

Required Vertical Accuracy = 19.6 cm NVA

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

CA_NorthernCA_2 (Work Unit 300407) - 2 counties covering approximately 911 square miles. The counties are: Tehama, Shasta

CA_NorthernCA_1 (Work Unit 300326) - 6 counties covering approximately 1603 square miles. The counties are: Lake, Marin, Mendocino, Napa, Solano, Sonoma

CA_NorthernCA_3 (Work Unit 300464) - 3 counties covering approximately 4241 square miles. The counties are: Lassen, Modoc, Shasta

CA_NorthernCA_4 (Work Unit 300465) - 4 counties covering approximately 2013 square miles. The counties are: Lassen, Modoc, Shasta, Siskiyou

CA_NorthernCA_5 (Work Unit 300466) - 6 counties covering approximately 3382 square miles. The counties are: Del Norte, Humboldt, Shasta, Siskiyou, Tehama, Trinity

A_NorthernCA_6 (Work Unit 300467) - 7 counties covering approximately 3481 square miles. The counties are: Curry, Del Norte, Humboldt, Jackson, Josephine, Siskiyou, Trinity

A_NorthernCA_7 (Work Unit 300468) - 5 counties covering approximately 3499 square miles. The counties are: Jackson, Klamath, Lake, Modoc, Siskiyou

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.

Microsoft Windows 10 ; ArcMap 10.7; ArcCatalog 10.7; TerraScan ver. 23; TerraModeler ver. 23; LP360.

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_NorthernCA_1, CA_NorthernCA_5, CA_NorthernCA_6, CA_NorthernCA_7

Based on a flying altitude of 2500 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.015 meters, this project was compiled to meet 0.27 meter horizontal accuracy at the 95% confidence level.

CA_NorthernCA_2, CA_NorthernCA_3, CA_NorthernCA_4

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 0.207 m RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 0.509 m at a 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

Tested NVA RMSEz = 3.73 cm

Tested 95th percentile value for VVA is : 24.84 cm

For more information see the USGS project report and the lidar reports. The links to these reports are provided 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 DEM is of good quality and data passes Non-Vegetated and Vegetated Vertical Accuracy specifications.

Data covers 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.