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Digital Surface Models (DSMs) of the Whale's Tail Marsh region, South San Francisco Bay, CA

Metadata Updated: December 11, 2025

This portion of the data release presents digital surface models (DSM) of the Whale's Tail Marsh region of South San Francisco Bay, CA. The DSMs have resolutions of 5 centimeters per pixel and were derived from structure-from-motion (SfM) processing of repeat aerial imagery collected from fixed-wing aircraft. Unlike a digital elevation model (DEM), a DSM represents the elevation of the highest object within the bounds of a cell. Vegetation, structures, and other objects have not been removed from the data. The raw imagery used to create these elevation models was acquired from an approximate altitude of 427 meters (1,400 feet) above ground level (AGL), using a Hasselblad A6D-100c camera fitted with an HC 80 lens, resulting in a nominal ground-sample-distance (GSD) of 2.5 centimeters per pixel. The acquisition flight lines were designed to provide approximately 50 percent overlap between adjacent flight lines (sidelap), with approximately 70 percent overlap between sequential images along the flight line (forelap). Survey control was established using an onboard camera-synchronized dual-frequency GPS system as well as ground control points (GCPs) distributed throughout the survey area and measured using survey-grade post-processed kinematic (PPK) GPS. Both the data from the onboard GPS and from the GPS used to measure the GCPs were post-processed using a nearby Continuously Operating Reference Station (CORS) station operated by the National Geodetic Survey (NGS). Structure-from-motion processing of these data was conducted using a "4D" processing workflow in which imagery from each of the different acquisition dates were co-aligned in order to increase relative spatial precision between the final data products. The resulting DSMs have been formatted as cloud optimized GeoTIFFs with internal overviews and masks to facilitate cloud-based queries and display.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources

No file downloads have been provided. The publisher may provide downloads in the future or they may be available from their other links.

Dates

Metadata Created Date September 12, 2025
Metadata Updated Date December 11, 2025

Metadata Source

Harvested from DOI USGS DCAT-US

Additional Metadata

Resource Type Dataset
Metadata Created Date September 12, 2025
Metadata Updated Date December 11, 2025
Publisher U.S. Geological Survey
Maintainer
Identifier http://datainventory.doi.gov/id/dataset/usgs-630807e2d34e3b967a8c15d1
Data Last Modified 2023-05-08T00:00:00Z
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://ddi.doi.gov/usgs-data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 19349da7-2308-4a3f-bb04-42dbe166ff80
Harvest Source Id 2b80d118-ab3a-48ba-bd93-996bbacefac2
Harvest Source Title DOI USGS DCAT-US
Metadata Type geospatial
Source Datajson Identifier True
Source Hash 08ec4727c6f0cf8cef6185a032eb3a613710b033438e8a4f2adcbb1e6140a40f
Source Schema Version 1.1

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