Joshua B. Logan Amy E. East Andrew C. Ritchie 20210702 GeoTIFF data release DOI:10.5066/P9HEDYNT Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/P9HEDYNT https://www.sciencebase.gov/catalog/item/605259afd34e7eb1cb3eb49b Joshua B. Logan Peter Dartnell Amy E. East Andrew C. Ritchie 2020 2.0 data release DOI:10.5066/P9HEDYNT Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey https://doi.org/10.5066/P9HEDYNT https://www.sciencebase.gov/catalog/item/5dfbba2fe4b0b5e61c073327 This portion of the data release presents a digital surface model (DSM) and hillshade of Whiskeytown Lake and the surrounding area derived from Structure from Motion (SfM) processing of aerial imagery acquired on 2020-11-10. Unlike a digital elevation model (DEM), the DSM represents the elevation of the highest object within the bounds of a cell. Vegetation, buildings and other objects have not been removed from the data. In addition, data artifacts resulting from noise and vegetation in the original imagery have not been removed. However, in unvegetated areas such as reservoir shorelines and deltas, the DSM is equivalent to a DEM because it represents the ground surface elevation. The raw imagery used to create this DSM was acquired from a manned aircraft on 2020-11-10. The acquisition flight was conducted by The 111th Group Aerial Photography, using a Hasselblad A6D-100c camera. The imagery was acquired from an approximate altitude of 880 meters (2,900 feet) above ground level, to produce a nominal ground sample distance (pixel size) of 5 centimeters (2 inches). An onboard dual-frequency GPS receiver was used to record the precise time and position of each image. Coordinates for ground control points consisting of photo-identifiable objects were measured independently using survey-grade post-processed kinematic (PPK) GPS. This digital surface model (DSM) was created to help evaluate the initial post-fire conditions on the exposed margins of Whiskeytown Lake as well as the exposed, unvegetated portions of the surrounding watersheds. It is intended for use by scientists, managers, and the general public. The DSM can be used with geographic information systems (GIS) software for research purposes. Additional information about the field activities from which these data were derived is available online at: http://cmgds.marine.usgs.gov/fan_info.php?fan=2020-627-FA Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Data used in creating this DSM were collected under the Department of the Interior, National Park Service Scientific Research and Collecting Permit WHIS-2018-SCI-0023, WHIS-2019-SCI-0011 and WHIS-2020-SCI-0006. 20201110 20201110 ground condition at time data were collected Complete None planned -122.63547 -122.51336 40.66341 40.59111 USGS Metadata Identifier USGS:605259afd34e7eb1cb3eb49b ISO 19115 Topic Category elevation Data Categories for Marine Planning Bathymetry and Elevation USGS Thesaurus topography topographic maps remote sensing geomorphology aerial photography image mosaics fires Marine Realms Information Bank (MRIB) keywords photography remote sensing fragile ecosystems None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC reservoir wildfires Carr fire Geographic Names Information System (GNIS) State of California Whiskeytown-Shasta-Trinity National Recreation Area Whiskeytown Lake None USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov https://www.sciencebase.gov/catalog/file/get/605259afd34e7eb1cb3eb49b?name=Whiskeytown_2020-11-10_DSM_25cm_browse.png Color shaded relief map of 2020-11-10 DSM. PNG Data collection was funded by the U.S. Geological Survey. Data acquisition was conducted by The 111th Group Aerial Photography. Data processing was done by the U.S. Geological Survey. Microsoft Windows 10, Agisoft PhotoScan version 1.4.4 through Agisoft Metashape 1.5.3, QGIS 3.04 through 3.12, and GDAL 3.0.4 through 3.1.0, Hasselblad Phocus 3.4.7, Novatel GrafNav 8.8. No formal attribute accuracy tests were conducted. No formal logical accuracy tests were conducted. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Horizontal positional accuracy was evaluated by comparing the positions of 24 independent photo-identifiable ground control check points measured with survey-grade post-processed kinematic (PPK) GPS with their estimated positions derived from the structure from motion (SfM) processing workflow. The root-mean-square error (RMSE) of the residual values of the measured positions versus the SfM-estimated positions was 0.070 meters. It should be noted that this estimate is for unvegetated, bare ground areas only. Additional sources of error such as noise or blurriness within the source imagery, poor terrain reconstruction in areas of uniform color and texture such as roads and parking lots, poor terrain reconstruction on small islands surrounded by water, and vegetation artifacts may cause additional errors in portions of the DSM which likely exceed the stated uncertainty bounds. Vertical positional accuracy was evaluated by comparing the elevations of 24 independent photo-identifiable ground control check points measured with survey-grade post-processed kinematic (PPK) GPS with their estimated elevations derived from the structure from motion (SfM) processing workflow. The root-mean-square error (RMSE) of the residual values of the measured positions versus the SfM-estimated elevations was 0.081 meters. It should be noted that this estimate is for unvegetated, bare ground areas only. Additional sources of error such as noise or blurriness within the source imagery, poor terrain reconstruction in areas of uniform color and texture such as roads and parking lots, poor terrain reconstruction on small islands surrounded by water, and vegetation artifacts may cause additional errors in portions of the DSM which likely exceed the stated uncertainty bounds. Aerial imagery was collected by the 111th Group, Inc. on 2020-11-10 between 20:49 and 22:10 Universal Coordinated Time (UTC) (12:49 to 14:10 Pacific Standard Time (PST)), using a Hasselblad A6D-100c mounted in a nadir orientation. The imagery was acquired from an approximate altitude of 890 meters (2,920 feet) above ground level, to produce a nominal ground sample distance (pixel size) of 5 centimeters (2 inches). A total of 1,283 images were acquired in the survey area, with an approximate 70 percent along-line image overlap (forelap) and 50 percent side-to-side overlap (sidelap). An onboard dual-frequency GPS receiver was used to record the precise shutter time and position of each image. 20201110 Patrick Belanger The 111th Group Inc mailing and physical

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San Martin CA 95046 408-683-9111 pat@the111th.com The GPS data from the aircraft onboard dual-frequency GPS was post processed using Precise Point Positioning (PPP) in the Novatel GrafNav GNSS post-processing software package. Precise positions for camera shutter event marks were interpolated using the Grafnav Camera Event Mark tool, and exported in NAD83(2011) spherical and projected coordinates. 2020 Joshua Logan U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7519 jlogan@usgs.gov Ground control was established by measuring the positions of approximately 84 photo-identifiable marks or objects using survey-grade post-processed-kinematic (PPK) GPS equipment. All measurements were referenced to a static base station operating on a temporary benchmark within the survey area. The position of the base station was established using the National Geodetic Survey Online Positioning User Service (OPUS). 2020 Joshua Logan U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7519 jlogan@usgs.gov Imagery from the raw Hasselblad 3FR format was converted to Hasselblad FFF format using the Hassleblad Phocus software package. The imagery exposure value (EV) was increased by +0.25 stops, and the chromatic aberration and vignetting corrections were applied under the Lens Correction tab. The distortion correction was not applied. The resulting adjusted images were exported using the JPG Max profile (JPG with Quality set to Maximum). 2020 Joshua Logan U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7519 jlogan@usgs.gov Structure from Motion (SfM) processing techniques were used to create the Digital Surface Model and Orthomosaic in the Agisoft Photoscan/Metashape software package using the following work flow: 1. The aerial imagery was loaded into Agisoft, and the camera positions were updated using the PPP post-processed onboard GPS data. 2. Initial image alignment was performed with the following parameters - Accuracy: 'high'; Pair selection: 'reference', 'generic'; Key point limit: 0 (unlimited); Tie point limit: 0 (unlimited). 3. Optimization and lens calibration parameters f, cx, cy, k1, k2, k3, p1, and p2 were included. 4. Ground control points (GCPs) previously measured with PPK GPS were manually identified and placed in the imagery. 5. Sparse point cloud error reduction was performed using an iterative gradual selection and camera optimization process with the following parameters: Reconstruction Uncertainty: 10; Projection Accuracy: 3; Reconstruction Error: 0.3. 6. A dense point cloud was created using the 'high' accuracy setting, with 'aggressive' depth filtering. 7. An initial Digital Surface Model (DSM) with a native resolution of 0.096 meters per pixel was created using points from the dense point cloud. An exterior boundary was digitized and used as a clipping mask to exclude obvious edge artifacts and large areas of interpolation. The DSM was exported to a GeoTIFF format with a 0.250-meter pixel resolution. 8. An RGB orthomosaic with a native resolution of 0.048 meters per pixel was created using the DSM as the orthorectification surface. The orthomosaic was exported to a GeoTIFF format at two resolutions: 0.050-meter pixels, and 0.250-meter pixels. 9. The shoreline boundary was manually digitized in QGIS using the orthomosaic as a visual reference. This was used as a clipping mask to remove water surface areas from the DSM using QGIS/GDALWARP. 10. The DSM was converted to a cloud optimized GeoTIFF format for compatibility with cloud storage services using the GDAL software package. The DSM was compressed using the lossless Deflate compression method, and NoData value set to -32767. A hillshade of the DSM was created in cloud optimized GeoTIFF format using GDAL. 2020 Joshua Logan U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7519 jlogan@usgs.gov Raster Pixel 31900 41156 Universal Transverse Mercator 10 0.9996 -123.00000 0.00000 500000.0 0.00 coordinate pair 0.250 0.250 Meters North American Datum of 1983, 2011 realization (NAD83(2011)). GRS 1980 6378137.00 298.257222101 North America Vertical Datum of 1988 (NAVD88) 0.001 meters Explicit elevation coordinate included with horizontal coordinates GeoTIFF GeoTIFF containing elevation values. Producer defined N/A Elevation relative to the North American vertical datum of 1988 (NAVD88) Producer defined 283.220 660.943 meters 0.001 U.S. Geological Survey - ScienceBase mailing and physical

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov The DSM (Whiskeytown_2020-11-10_DSM_25cm.tif) and hillshade (Whiskeytown_2020-11-10_DSM_25cm_hll.tif) are available as Cloud Optimized GeoTIFF files. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. GeoTIFF GDAL 3.1.0dev Cloud Optimized GeoTIFF contains Digital Surface Model (DSM) with single-precision floating-point values compressed using the Deflate lossless compression method. No data value is -32767. none 1292 https://www.sciencebase.gov/catalog/file/get/605259afd34e7eb1cb3eb49b?name=Whiskeytown_2020-11-10_DSM_25cm.tif https://prod-is-usgs-sb-prod-publish.s3.amazonaws.com/605259afd34e7eb1cb3eb49b/Whiskeytown_2020-11-10_DSM_25cm.tif https://www.sciencebase.gov/catalog/item/605259afd34e7eb1cb3eb49b https://doi.org/10.5066/P9HEDYNT Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the 25-centimeter DSM. The second link is for accessing the DSM on cloud-based storage and can be used for cloud-based queries or viewing. The third link points to a landing page with the DSM and a hillshade, metadata, and browse image. The fourth link points to the landing page for the entire data release, including links to pages of the various data files. GeoTIFF GDAL 3.1.0dev Cloud Optimized GeoTIFF contains hillshade of Digital Surface Model (DSM) with 8-bit unsigned integer values compressed using the Deflate lossless compression method. No data value is 0. none 505 https://www.sciencebase.gov/catalog/file/get/605259afd34e7eb1cb3eb49b?name=Whiskeytown_2020-11-10_DSM_25cm_hll.tif https://prod-is-usgs-sb-prod-publish.s3.amazonaws.com/605259afd34e7eb1cb3eb49b/Whiskeytown_2020-11-10_DSM_25cm_hll.tif https://www.sciencebase.gov/catalog/item/605259afd34e7eb1cb3eb49b https://doi.org/10.5066/P9HEDYNT Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download hillshade version of the 25-centimeter DSM. The second link is for accessing the hillshade on cloud-based storage and can be used for cloud-based queries or viewing. The third link points to a landing page with the DSM and a hillshade, metadata, and browse image. The fourth link points to the landing page for the entire data release, including links to pages of the various data files. None. These data can be viewed with GIS software or other software capable of displaying geospatial raster data. 20210702 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998