Joshua B. Logan
Amy E. East
Andrew C. Ritchie
20210702
Topographic digital surface model (DSM) for Whiskeytown Lake and surrounding area, 2020-11-10
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
Bathymetry, topography and orthomosaic imagery for Whiskeytown Lake, northern California
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
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
13025 Murphy Ave. Suite 100
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
Denver Federal Center, Building 810, Mail Stop 302
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