3DEP Spatial Metadata

Work unit Extent Spatial Metadata (WESM)

The Work unit Extent Spatial Metadata (WESM) (geopackage link here; CSV table link here) contains information about what Lidar Point Cloud (LPC) and source DEMs (also known as Original Product Resolution (OPR) DEMs) work units have been processed and made available to the public. It contains information about lidar projects, including lidar quality level, data acquisition dates, and links to project-level metadata.  A new WESM is written almost daily as more lidar projects are processed and published.

Spatial Metadata 

• The WESM geopackage contains links to the location of the source data (LPC and source DEMs) as well as the contractor and project metadata for each work unit.

• The WESM contains work unit and project IDs, as well as a new field that indicates “status” by product type (lidar point cloud [LPC], source DEMs, 1m DEMs, and seamless DEMs).   

  • The status refers to whether that product type meets 3DEP requirements, meets the requirements with variances, or does not meet 3DEP requirements. 

  • There is an “expected to meet” temporary placeholder for the 1m and Seamless products that is updated when the data validation of the entire project is complete.   

  • A reason code (text field) explains why a publication unit was placed in a specific category (for example, the reason why a dataset did not meet 3DEP standards).   

• The WESM also contains links to the location of the source data (LPC and source DEMs) as well as the contractor and project metadata for each work unit.  The updated WESM files will be served as geopackages. 

For more information about product metadata, please see the 3DEP standards and specifications webpage. 

WESM Data Dictionary

The WESM Data Dictionary defines the columns in the spatial metadata attribute table. For more information, please see the WESM Data Dictionary webpage. 

Lidar Publishing Process 

• The original source DEMs created by the lidar contractors (also called “original product resolution” [OPR] DEMs) and lidar point clouds are published by individual work unit after data validation is complete, rather than waiting for the entire lidar project to be delivered and complete the USGS data validation process. The process is described in the diagram below. XML metadata produced by the lidar contractor will be provided on The National Map (TNM) by work unit via HTTPS. 

Work Unit and Project Reports, and Vertical Accuracy Information

• A new work unit report is provided with each published work unit (beginning in early July 2020).

• The lidar contractor ground survey reports, checkpoints, breaklines, and USGS vertical accuracy test results are available at the project level via HTTPS when all work units are published.

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