Metadata: Identification_Information: Citation: Citation_Information: Originator: Joshua B. Logan Originator: Amy E. East Publication_Date: 20230111 Title: Digital surface model (DSM) and digital elevation model (DEM) of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01 Geospatial_Data_Presentation_Form: GeoTIFF Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9J9CHOH Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P9J9CHOH Online_Linkage: https://www.sciencebase.gov/catalog/item/63780c9ad34ed907bf70044b Larger_Work_Citation: Citation_Information: Originator: Joshua B. Logan Originator: Amy E. East Publication_Date: 2023 Title: Aerial imagery and structure-from-motion data products from a UAS survey of the Los Padres Reservoir delta, Carmel River valley, CA, 2017-11-01 Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9J9CHOH Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, CA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P9J9CHOH Online_Linkage: https://www.sciencebase.gov/catalog/item/63728580d34ed907bf6c6a0f Description: Abstract: This portion of the data release presents a digital surface model (DSM) and digital elevation model (DEM) of the exposed Los Padres Reservoir delta where the Carmel River enters the reservoir. The DSM and DEM have a resolution of 10 centimeters per pixel and were derived from structure-from-motion (SfM) processing of aerial imagery collected with an unoccupied aerial system (UAS) on 2017-11-01. The DSM represents the elevation of the highest object within the bounds of a cell, including vegetation, woody debris and other objects. The DEM represent the elevation of the ground surface where it was visible to the acquisiton system. Due to the nature of SfM processing, the DEM may not represent a true bare-earth surface in areas of thick vegetation cover; in these areas some DEM elevations may instead represent thick vegetation canopy. The raw imagery used to create these elevation models was acquired with a UAS fitted with a Ricoh GR II digital camera featuring a global shutter. The UAS was flown on pre-programmed autonomous flight lines spaced to provide approximately 70 percent overlap between images from adjacent lines. The camera was triggered at 1 Hz using a built-in intervalometer. The UAS was flown at an approximate altitude of 100 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. The raw imagery was geotagged using positions from the UAS onboard single-frequency autonomous GPS. Twenty temporary ground control points (GCPs) consisting of small square tarps with black-and-white cross patterns were distributed throughout the area to establish survey control. The GCP positions were measured using real-time kinematic (RTK) GPS, using corrections from a GPS base station located on a benchmark designated SFML, located approximately 1 kilometer from the study area. The DSM and DEM have been formatted as cloud optimized GeoTIFFs with internal overviews and masks to facilitate cloud-based queries and display. Purpose: These data are intended to be used to characterize the position, elevation, volume, and morphology of the Los Padres Reservoir delta sediment where the Carmel River enters the reservoir. This assessment of reservoir sediment was made in response to the 2016 Soberanes Fire in the upper Carmel watershed, followed by high flows during water year 2017. Supplemental_Information: Additional information about the field activity from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-635-FA Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20171101 Currentness_Reference: ground condition at time data were collected Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -121.66731 East_Bounding_Coordinate: -121.66118 North_Bounding_Coordinate: 36.38117 South_Bounding_Coordinate: 36.37326 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: Bathymetry and Elevation Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: topography Theme_Keyword: topographic maps Theme_Keyword: remote sensing Theme_Keyword: geomorphology Theme_Keyword: aerial photography Theme_Keyword: image mosaics Theme_Keyword: geospatial datasets Theme_Keyword: structure from motion Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: photography Theme_Keyword: remote sensing Theme_Keyword: aerial and satellite photography Theme_Keyword: altimetry Theme_Keyword: orthophotography Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CHMRP Theme_Keyword: Pacific Coastal and Marine Science Center Theme_Keyword: PCMSC Theme_Keyword: Unmanned aerial system Theme_Keyword: UAS Theme_Keyword: Structure-from-motion Theme_Keyword: SfM Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:63780c9ad34ed907bf70044b Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: State of California Place_Keyword: Carmel River Place_Keyword: Monterey County Access_Constraints: None Use_Constraints: 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/63780c9ad34ed907bf70044b?name=LosPadresReservoir_2017-11-01_DSM_10cm_browse.jpg&allow=openTrue Browse_Graphic_File_Description: Color-shaded relief DEM of the Los Padres Reservoir delta. Browse_Graphic_File_Type: JPEG Native_Data_Set_Environment: Microsoft Windows 10, Agisoft PhotoScan version 1.4.4 through Agisoft Metashape 1.5.3, ESRI ArcGIS 10.6 through 10.7, Exiftool, Geosetter 3.4.16, QGIS 3.26, and GDAL 3.5.1 Cross_Reference: Citation_Information: Originator: Smith, D.P. Originator: Kvitek, R. Originator: Aiello, I. Originator: Iampietro, P. Originator: Quan, C. Originator: Paddock, E. Originator: Endris, C. Originator: Gomez, K. Publication_Date: 2009 Title: Fall 2008 Stage-Volume Relationship for Los Padres Reservoir, Carmel Valley, California: Prepared for the Monterey Peninsula Water Management District Other_Citation_Details: Smith, D.P., Kvitek, R., Aiello, I., Iampietro, P., Quan, C., Paddock, E., Endris, C, and Gomez, K., 2009, Fall 2008 Stage-Volume Relationship for Los Padres Reservoir, Carmel Valley, California: Prepared for the Monterey Peninsula Water Management District. The Watershed Institute, California State University Monterey Bay, Publication no. WI-2009-2, 30 pp. Online_Linkage: https://ccows.csumb.edu/pubs/reports/CCoWS_MPWMD_LosPadres_StageVol_2008_090508.pdf Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No formal attribute accuracy tests were conducted. Logical_Consistency_Report: No formal logical accuracy tests were conducted. Completeness_Report: Dataset is considered complete for the information presented, as described in the abstract. For the purpose of creating the DSM and the DEM, the small exposed 3 x 4 meter island located in the reservoir approximately 10 meters north of the delta was omitted. Users are advised to read the rest of the metadata record carefully for additional details. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracy was estimated by comparing ground control point (GCP) positions measured with RTK GPS measurements to their SfM-estimated positions. Due to the time-intensive process of placing GCPs in the field, all available GCPs were used for registration and camera optimization in the SfM processing workflow during the creation of the final SfM data products. To evaluate the horizontal positional accuracy of the final SfM alignments, each GCPs was disabled one-at-a-time using a python script to create a 'temporary check point'. With a single GCP temporarily disabled, camera optimization was performed with all lens parameters fixed, and all other GCPs enabled. The residual errors of the check point relative to its GPS-measured position were recorded. After all temporary check point iterations were complete, the root-mean-square error (RMSE) and mean-absolute error (MAE) were calculated. The resulting horizontal RMSE was 0.025 meters (MAE 0.020 meters). The addition of the estimated horizontal GPS uncertainty (0.020 meters) in quadrature results in a total horizontal accuracy estimate of 0.032 meters. It should be noted that this error estimate is for areas of bare ground or low vegetation where GCPs were placed. Additional sources of error such as poor image-to-image point matching due to vegetation or uniform substrate texture (such as sand) resulting in poor surface reconstruction may cause localized errors in some portions of the point clouds to exceed this estimate. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Vertical accuracy was estimated using two methods to compare the DSM and DEM vertical elevations to concurrently collected real-time kinematic (RTK) GPS measurements. The first method used a comparison of ground control point (GCP) positions measured with RTK GPS measurements to their SfM-estimated positions. Due to the time-intensive process of placing GCPs in the field, all available GCPs were used for registration and camera optimization in the SfM processing workflow during the creation of the final DSM and DEM. To evaluate the vertical positional accuracy of the models after processing was completed, a subset of GCPs was disabled one-at-a-time using a python script to create 'temporary check points'. With a single GCP temporarily disabled, camera optimization was performed with all lens parameters fixed, and all other GCPs enabled. The residual errors of the check point relative to its GPS-measured position were recorded. After all temporary check point iterations were complete, the root-mean-square error (RMSE) and mean-absolute error (MAE) were calculated. The resulting vertical RMSE was 0.039 meters (MAE 0.028 meters). The addition of the estimated vertical GPS uncertainty (0.040 meters) in quadrature results in a total vertical accuracy estimate of 0.056 meters for the point cloud. It should be noted that this error estimate is for areas of bare ground or low vegetation where GCPs were placed. Additional sources of error such as poor image-to-image point matching due to vegetation or uniform substrate texture (such as sand) resulting in poor surface reconstruction may cause localized errors in some portions of the point clouds to exceed this estimate. A second method was used to attempt to quantify the vertical errors in areas away from the GCPs. During field data collection, topographic measurements on unvegetated areas were collected with backpack-mounted RTK GPS. These measurements were compared to the elevation models using bilinear interpolation at each GPS point to derive additional accuracy estimates. - For the DSM, the vertical RMSE of 821 backpack-mounted RTK GPS measurements compared to the DSM elevations at those locations was 0.059 meters (MAE 0.047 meters). The mean-error (vertical bias) of the GPS measurements relative to DSM elevations was 0.017 meters, meaning the DSM was, on average, lower than the GPS measurements. The addition of the estimated vertical uncertainty of the backpack-mounted GPS (0.050 meters) in quadrature results in a total vertical accuracy estimate of 0.077 meters for the DSM using this method. - For the DEM, the vertical RMSE of 821 backpack-mounted RTK GPS measurements compared to the DEM elevations at those locations was 0.060 meters (MAE 0.049 meters). The mean-error (vertical bias) of the GPS measurements relative to DSM elevations was 0.024 meters, meaning the DEM was, on average, lower than the GPS measurements. The addition of the estimated vertical uncertainty of the backpack-mounted GPS (0.050 meters) in quadrature results in a total vertical accuracy estimate of 0.078 meters for the DEM using this method. These slightly higher error estimates are due in part to the less precise nature of the backpack-mounted GPS measurements. However, these backpack-mounted GPS comparisons do provide a more conservative, spatially distributed estimate of the true accuracy of the elevations models than the GCP check point method. We present both estimates here to provide the end-user with a more complete understanding of the accuracy of the final data products. Lineage: Process_Step: Process_Description: Aerial imagery was collected using a Department of Interior-owned 3DR Solo quadcopter fitted with a Ricoh GR II digital camera featuring a global shutter. The camera was mounted using a fixed mount on the bottom of the UAS and oriented in an approximately nadir orientation. During image acquisition the UAS was flown on pre-programmed autonomous flight lines at an approximate altitude of 100 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 2.6 centimeters per pixel. The flight lines were spaced to provide approximately 70 percent overlap between images from adjacent lines. The camera was triggered at 1 Hz using a built-in intervalometer and was programmed to acquire imagery in JPG format. Before each flight, the camera digital ISO, aperture and shutter speed were manually set to adjust for ambient light conditions. Although these settings were changed between flights, they were not permitted to change during a flight; thus, the images from each flight were acquired with consistent camera settings. Process_Date: 20171101 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Joshua Logan Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Country: US Contact_Voice_Telephone: 831-460-7519 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: jlogan@usgs.gov Process_Step: Process_Description: Ground control was established using ground control points (GCPs) consisting of small square tarps with black-and-white cross patterns placed on the ground surface throughout the survey area. The GCP positions were measured using survey-grade GPS receivers operating in real-time kinematic (RTK) mode. For each GCP measurement the GPS receiver was placed on a fixed-height tripod and set to occupy each GCP for a minimum occupation time of one minute. The RTK corrections were referenced to a GPS base station occupying a previously established benchmark designated SFML, located on the Los Padres Reservoir dam approximately 1 kilometer from the survey area. In order to ensure consistency with historic surveys, the previously established position for SFML published in Smith and others, 2009 was used for the real-time surveys. After the survey, the static occupation on SFML was submitted to the National Geodetic Survey (NGS) Online Positioning User Service (OPUS). Process_Date: 20171101 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Joshua Logan Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7519 Contact_Electronic_Mail_Address: jlogan@usgs.gov Process_Step: Process_Description: The image files were renamed using a custom python script. The file names were formed using the following pattern Fx-YYYYMMDDThhmmssZ_Ryz.*, where: - Fx = Flight number - YYYYMMDDThhmmssZ = date and time in the ISO 8601 standard, where 'T' separates the date from the time, and 'Z' denotes UTC ('Zulu') time. - Ry = RA or RB to distinguish camera 'RicohA' from 'RicohB' - z = original image name assigned by camera during acquisition - * = file extension (JPG or DNG) The approximate image acquisition coordinates were added to the image metadata (EXIF) ('geotagged') using the image timestamp and the telemetry logs from the UAS onboard single-frequency 1-Hz autonomous GPS. The geotagging process was done using the Geosetter software package. To improve timestamp accuracy, the image acquisition times were adjusted to true ('corrected') UTC time by comparing the image timestamps with several images taken of a smartphone app ('Emerald Time') showing accurate time from Network Time Protocol (NTP) servers. For this survey, +00:00:01 (1 second) was added to the image timestamp to synchronize with corrected UTC time. The positions stored in the EXIF are in geographic coordinates referenced to the WGS84(G1150) coordinate reference system (EPSG:4979), with elevation in meters relative to the WGS84 ellipsoid. Additional information was added to the EXIF using the command-line 'exiftool' software with the following command: exiftool ^ -P ^ -IPTC:Credit="U.S. Geological Survey" ^ -IPTC:Contact="pcmsc_data@usgs.gov" ^ -EXIF:Copyright="Public Domain" ^ -XMP:UsageTerms="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 for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty." ^ -EXIF:ImageDescription="Low-altitude aerial image of the Los Padres Reservoir delta area, Carmel River valley, California, USA, from USGS field activity 2017-635-FA; https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-635-FA" ^ -XMP:Event="Unoccupied Aircraft System survey of Los Padres Reservoir delta area during USGS field activity 2017-635-FA." ^ -EXIF:GPSAreaInformation="Position from UAS onboard autonomous single-frequency GNSS." ^ -EXIF:GPSMapDatum="EPSG:4979 (WGS 84)" ^ -EXIF:Artist="U.S. Geological Survey, Pacific Coastal and Marine Science Center" ^ -IPTC:CopyrightNotice="Public Domain. Please credit U.S. Geological Survey." ^ -IPTC:Caption-Abstract="Aerial image of the Los Padres Reservoir delta area and Carmel River, Carmel River valley, California, USA, from an Unoccupied Aircraft System (UAS) during USGS field activity 2017-635-FA." ^ -sep ", " ^ -keywords="Carmel River, Los Padres Reservoir, Monterey County, California, 2017-635-FA, Unoccupied Aircraft System, UAS, drone, aerial imagery, U.S. Geological Survey, USGS, Pacific Coastal and Marine Science Center" ^ -comment="Aerial image of the Los Padres Reservoir delta area and Carmel River, Carmel River valley, California, USA, from an Unoccupied Aircraft System (UAS) during USGS field activity 2017-635-FA."^ -Orientation= ^ -XMP:AttributionURL="https://doi.org/10.5066/P9J9CHOH" ^ -OffsetTime*=+00:00 -AllDates+=7 ^ -r f* ^ -ext DNG ^ -ext JPG Additional metadata tags were populated in the imagery metadata using the following command: exiftool ^ -P ^ "-XMP-photoshop:Credit