Data Management Plan

Dataset Description: The CA Central Valley Lidar 2016 D16 Mod 002: CA Sacramento Delta Lidar 2017 D16 lidar project called for the planning, acquisition, processing, and production of derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2

Ground Conditions: Lidar was collected from December 9, 2017 through January 21, 2018 by Woolpert, while no snow was on the ground and rivers were at or below normal levels. Saturated or partially flooded farm fields were identified following data acquisition. Through technical guidance discussions with USGS and the California Department of Water, it was determined such areas shall not be considered hydrologic features. Intermittently, partially flooded, irregular, and apparently non-agricultural fields were treated as hydrologic features. In all cases, best professional judgement was used in determination of treatment. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Woolpert established 35 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 143 independent accuracy checkpoints (75 NVA points and 68 VVA points), were collected and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

Lineage Statement:
This data set was downloaded from the CA DWR http site and processed to make it available for custom download from the Data Access Viewer (DAV) and for bulk download from https.

Process Steps:

• 2019-06-03 00:00:00 - Lidar Point Cloud Classification: The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" lidar returns. This process determined Processed, but Unclassified (Class 1), Bare Earth Ground (Class 2), Low Noise (Class 7), Water (Class 9), Ignored Ground (Class 10), Bridge Decks (Class 17) and High Noise (Class 18). The bare-earth (Class 2 - Ground) lidar points underwent a manual QA/QC step to verify the quality of the DEM as well as a peer-based QC review. This included a review of the DEM surface to remove artifacts and ensure topographic quality. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through a semi-automated process. All ground (Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (Class 9) using TerraScan/LP360 macro functionality. A buffer of 0.7 meters was also used around each hydro-flattened feature to classify these ground (Class 2) points to Ignored ground (Class 10). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and pilot study areas. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Woolpert proprietary software and LP360 was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.
• 2017-12-09 00:00:00 - The data was developed based on a horizontal datum/projection of NAD83 (NSRS2007) UTM Zone 10 (EPSG 3717) meters, and a vertical datum of NAVD88 (GEOID12B), US survey feet. lidar point cloud data was delivered as LAS 1.4 files formatted to 1,706 individual 1,500-meter x 1,500-meter tiles. Product: Processed, classified lidar point cloud data tiles in LAS 1.4 format. Geographic Extent: Approximately 1,312 square miles across several counties in central California.
• 2021-09-20 00:00:00 - The NOAA Office for Coastal Management (OCM) downloaded 1706 las format files from this CA DWR http site: http://gisarchive.cnra.ca.gov/iso/ImageryBaseMapsLandCover/LIDAR/DeltaLIDAR2017/point_cloud/tilecls/. The data were in UTM Zone 10 (NSRS 2007), meters coordinates and in NAVD88 (Geoid12B) elevations in US survey feet. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 17 - Bridge Decks, 18 - High Noise. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 7, 9, 10, 17, 18. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges. 2. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid 12B model, to convert from vertical units of feet to meters, to convert from UTM Zone 10 (NSRS2007) meters coordinates to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to https.

Data is available online for bulk and custom downloads.