ErddapSTAC

A simple programme to create a STAC catalog for the datasets served by instances of NOAA's Erddap server software.

Motivation

Erddap servers provide a consistent interface to environmental data, and previous solutions have been created to allow federated search across instances of Erddap (e.g. ). However, STAC provides a simple way of bridging the gap between these Erddap focussed approaches to federated search and integration with more genereic spatio-temporal dataset search.

What is Erddap?

ERDDAP is a scientific data server that gives users a simple, consistent way to download subsets of gridded and tabular scientific datasets in common file formats and make graphs and maps.

What is STAC?

STAC is the SpatioTemporal Asset Catalog specification which aims to make geospatial assets openly searchable and crawlable.

Data Modeling

In the current implementation the following design approach has been taken:

• There is one top level STAC Catalog which represents all crawled instances of Erddap
• Each encountered Erddap dataset is represented as a STAC Collection in that top level STAC Catalog
• Each STAC Collection is also linked to a STAC Item which represents the JSON and NetCDF file offereings of the dataset from an Erddap server

A next iteration will use the subset variables in the Erddap metadata to provide a higher level of granularity at the STAC Item level and better differentiation between the contents of the STAC Collection and STAC Item records.

Getting set up

1. Ensure you have a golang environment set up on your target machine
2. Clone this git repository
3. There are no further external dependencies in the software

TODO

1. Add summaries, assets and item_assets to the STAC Collection definition
2. Handle null times in the STAC Collection definition
3. Improve the GeoJSON Feature representations
4. Create a Docker container to allow swift deployment of this software anywhere
5. Map license specifications to SPDX entries
6. Look at the STAC Grid extension and see if any mapping from Erddap Griddap types is worthwhile
7. Use the subsetVariables metadata field on Erddap datasets to improve the STAC Item granularity