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Digital surface models (DSMs) for the intertidal zone at Post Point, Bellingham Bay, WA, 2019-06-06

Metadata Updated: January 21, 2026

This portion of the data release presents digital surface models (DSMs) and hillshade images of the intertidal zone at Post Point, Bellingham Bay, WA. The DSMs were derived from structure-from-motion (SfM) processing of aerial imagery collected with an unmanned aerial system (UAS) on 2019-06-06. Unlike a digital elevation model (DEM), the DSMs represent 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 in the original imagery have not been removed. The DSMs are presented with two resolutions: one DSM, covering the entire survey area, has a resolution of 4 centimeters per pixel; the other DSM which was derived from a lower-altitude flight, covers an inset area within the main survey area and has a resolution of 2 centimeters per-pixel. The raw imagery used to create these DSMs was acquired using 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. For the main DSM, the UAS was flown at an approximate altitude of 70 meters above ground level (AGL), resulting in a nominal ground-sample-distance (GSD) of 1.8 centimeters per pixel. For the higher-resolution DSM, the UAS was flown at an approximate altitude of 35 meters (AGL), resulting in a nominal ground-sample-distance (GSD) of 0.9 centimeters per pixel. The raw imagery was geotagged using positions from the UAS onboard single-frequency autonomous GPS. Nineteen temporary ground control points (GCPs) were distributed throughout each survey area to establish survey control. The GCPs consisted of a combination of small square tarps with black-and-white cross patterns and "X" marks placed on the ground using temporary chalk. The GCP positions were measured using post-processed kinematic (PPK) GPS, using corrections from a GPS base station located approximately 5 kilometers from the study area. The DSMs and hillshade images 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

Dates

Metadata Created Date January 13, 2026
Metadata Updated Date January 21, 2026

Metadata Source

Harvested from DOI USGS DCAT-US

Additional Metadata

Resource Type Dataset
Metadata Created Date January 13, 2026
Metadata Updated Date January 21, 2026
Publisher U.S. Geological Survey
Maintainer
Identifier http://datainventory.doi.gov/id/dataset/USGS_5ef53d9182ced62aaae6a0aa
Data Last Modified 2021-02-22T00:00:00Z
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
Datagov Dedupe Retained 20260120174654
Harvest Object Id a4b41e33-f5c5-44d5-8cf9-551aed6dde38
Harvest Source Id 2b80d118-ab3a-48ba-bd93-996bbacefac2
Harvest Source Title DOI USGS DCAT-US
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": -122.5201, 48.7113, -122.5201, 48.7204, -122.5156, 48.7204, -122.5156, 48.7113, -122.5201, 48.7113}
Source Datajson Identifier True
Source Hash 30ae3983813ba2454c16b4bd85d154874de2171044292741acb96147658c237f
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -122.5201, 48.7113, -122.5201, 48.7204, -122.5156, 48.7204, -122.5156, 48.7113, -122.5201, 48.7113}

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