Software update for data extraction of a geographical area from EFAS gridded datasets

On 03 December 2025, the software handling area extraction for gridded datasets will be updated to a new version. The new version fixes an issue that caused an interpolation of the data during the area extraction - assigning new point values at new locations. In reality, it should have only performed a crop, preserving the original point data and their locations.

Summary:

  1. Original point data and their locations are preserved during the area extraction.

  2. Masking of areas outside of the user input area was introduced for the polar_stereographic grid type. This is because cropping for these projection-based grids is only approximate in terms of coordinates and projection parametrisation and especially so for a non-spherical Earth. For example, if a user requests data for the bounding box “N, W, S, E” it will still receive a dataset containing the full original grid with valid data only for that region and missing values assigned for the pixels outside of the selected region.

  3. These changes will affect EFAS version 4 and older for the following datasets:

    • River discharge and related forecasted data by the European Flood Awareness System,

    • River discharge and related historical data from the European Flood Awareness System,

    • Reforecasts of river discharge and related data by the European Flood Awareness System