Precursor Coincident Dataset (PCD)#
This page describes the metadata for the Precursor Coincident Dataset (PCD), which consists of 13 high-quality 3D measurement sites across the contiguous United States (CONUS).
Download the Data#
To download and generate the dataset assets in both GeoJSON (.geojson) and
GeoParquet (.geoparquet) formats, run the following command from the root of
the repository:
pixi run python src/coincident/scripts/generate_pcd.py
Note
This will create a new data subdirectory in your current working directory if data does not already exist and download all PCD metadata as GeoJSONs and Geoparquets. The total disk space required for all of these files is under 100mb.
Dataset Description#
The PCD was generated by identifying regions of overlapping data from key airborne and spaceborne sensors. The provided files contain STAC-compliant metadata describing the spatial and temporal footprints for each data source at each site.
Airborne Lidar: USGS 3DEP, NEON, and NCALM acquisitions.
Satellite Lidar: ICESat-2 (ATL06) and GEDI (L2A).
Stereo Imagery: Maxar in-track stereo images.
The output from the download script includes GeoJSONs for each data provider and data type (e.g., ALS footprints, ICESat-2 tracks, stereo footprints, and the final four-way overlap area). The metadata includes sensor details, acquisition times, quality metrics, and terrain characteristics derived from the Copernicus 30m DEM and NLCD 2021 land cover data.
Methodology & Composition#
The 13 final sites were selected through a multi-stage filtering workflow that prioritized high-quality, temporally coincident data (typically within a ±30 day window). The workflow required a minimum of 10 km² of four-way overlap between all sensor types. Candidate sites were characterized by land cover and manually reviewed for data quality, ensuring a diverse set of geographies and land types. Diverse stereo acquisition geometry, diverse aerial lidar quality, and spaceborne altimetry noise filtering were also taken into account.
The final sites include:
9 USGS 3DEP sites spanning glacial terrain, forests, shrublands, urban areas, and wetlands.
3 NEON sites focused on mixed hardwood and conifer forests.
1 NCALM site from a dense drone-based SfM survey.
Provider |
PCD Site Identifier |
Description |
Fourway Overlap Area (km²) |
Aerial Lidar Start Date |
Aerial Lidar End Date |
|---|---|---|---|---|---|
USGS |
|
Urban over San Francisco |
55 |
2023-04-20 |
2023-04-20 |
USGS |
|
Desert / Mine in southern Arizona |
53 |
2021-09-27 |
2021-11-17 |
NEON |
|
Deciduous / Conifer in northern Utah |
25 |
2021-05-20 |
2021-05-21 |
USGS |
|
Cropland in eastern Nebraska |
540 |
2020-11-16 |
2020-12-09 |
USGS |
|
Urban / Wetlands in Green Bay, Wisconsin |
89 |
2020-05-07 |
2020-05-07 |
USGS |
|
Mixed LULC in southern Georgia |
745 |
2020-02-02 |
2020-03-28 |
NCALM |
|
Southern San Andreas fault line |
12 |
2020-02-15 |
2020-02-18 |
USGS |
|
Coniferous / Mountainous in northern Yosemite National Park |
84 |
2019-10-07 |
2019-10-23 |
USGS |
|
Shrubland / Grassland in western Texas |
165 |
2019-09-11 |
2019-10-20 |
NEON |
|
Mixed hardwood forest in eastern New Hampshire |
32 |
2019-08-25 |
2019-08-25 |
USGS |
|
Coniferous / Mountainous in the Colorado Rockies |
184 |
2019-08-21 |
2019-09-19 |
USGS |
|
Glaciers / Mountainous in western Wyoming |
681 |
2019-07-26 |
2019-09-22 |
NEON |
|
Conifer forest in southern Washington state |
18 |
2019-07-12 |
2019-07-15 |
Note
The NCALM site’s “ground truth” is not aerial lidar, but rather dense aerial SfM from a drone
While this initial dataset focuses on four-way overlap, it excludes some regions
like bathymetric zones where stereo imagery is less effective. However, users
are encouraged to use the coincident package to find three-way overlaps (e.g.,
ALS, ICESat-2, GEDI) for these and other applications.