Overview

Vyperdatum performs vertical datum transformations for coastal and hydrographic data within the PROJ/GDAL ecosystem. NOAA’s separation grids and a PROJ database augmented with NOAA metadata are used to convert between tidal, orthometric, and ellipsoidal vertical datums (for example, NAD83(2011) ellipsoid heights to MLLW or NAVD88) while the full coordinate reference system metadata is retained.

A high-level Transformer is provided. The transformer is constructed from a source CRS and a target CRS and is then applied to point-cloud and raster files through a single transform entry point.

Typical use cases

  • Hydrographic surveys are normalized to charting datums for ENC/RNC and bathymetric products.

  • Inputs are prepared for coastal flood, storm surge, and inundation models that require a specific vertical datum.

  • Coordinates are converted between ellipsoidal, orthometric, and tidal datums for coastal GNSS and GNSS-tide workflows.

How it works

Transformation steps can be inferred automatically from crs_from and crs_to, or prescribed explicitly when fine-grained control over the pipeline is required. Under the hood, a PROJ database augmented with NOAA grids and metadata is used. NOAA’s grid files and the updated proj.db are not bundled with the package; these are downloaded separately, and the VYPER_GRIDS environment variable is pointed at their location. The Installation and Environment and PROJ configuration pages describe this setup.

Relationship to the National Bathymetric Source

Vyperdatum can be used as a standalone package as long as the separation grids and the custom proj.db are available. Within NOAA, Vyperdatum is used across the National Bathymetric Source (NBS) pipeline, where it is relied upon by the fuse software. Compatibility with the NBS source code is treated as a constraint on Vyperdatum changes.