Polytope
Digital Twin Outputs in Destination Earth can be accessed using the DEDL provided Harmonised Data Access (HDA), but also the native polytope client. HDA can be used to access all data from the DestinE Data Portfolio using one API. HDA interacts with the polytope client to obtain the Digital Twin outputs.
Try out the ClimateDT-ParameterPlotter.ipynb provided by the DestinE-DataLakeLab to obtain a sample plot for each of the possible parameters from the ClimateDT.
Polytope is a horizontally scalable service which provides RESTful data access API over HTTPS, allowing access to high-performance data storage over the Internet. It implements access control and is also capable of federating access to data between different DEDL data bridges. Its purpose within Destination Earth is to expose the data stored in the FDB (on the DEDL Data Bridge) to the DESP and to other parts of the DEDL.
Using polytope as an open-source service, users can request arbitrary n-dimensional stencils (“polytopes”) of data, from highly-structured n-dimensional datasets. The data extraction is performed server-side (collocated with the data), resulting in large data reduction prior to transmission and less complexity for the user. For example, a user could request a polytope describing a flight path – simultaneously crossing temporal and spatial axes. Polytope will return just a few bytes of data rather than large structured arrays of geo-spatial data which must be further post-processed by the user.
Users can access the Polytope service via the REST API exposed by Polytope, or via the polytope-client Python package. The client includes a Python API and a command line tool (CLI) for accessing Polytope services.
Polytope Service Documentation:
https://polytope-client.readthedocs.io/en/latest/index.html
The detailed API and definition of each endpoint and parameters is available in the polytope - ecmwf.Swagger UI at:
https://polytope.ecmwf.int/openapi/
Describing the Variables
DestinE Parameter Portfolios
https://confluence.ecmwf.int/display/DDCZ/DestinE+Parameter+Portfolios
Examples
See https://github.com/destination-earth/DestinE-DataLake-Lab/tree/main/HDA