Coordinate systems

Spatial data requires careful attention to coordinate reference systems (CRS). This page explains how earthkit-hydro handles coordinates and what you need to know.

Importance of coordinate systems

River networks and input data must use compatible coordinate systems for operations like:

  • Locating monitoring stations

  • Extracting catchment boundaries

  • Overlaying with other spatial data

  • Calculating distances

Mismatched coordinate systems lead to incorrect results or errors.

Supported systems

earthkit-hydro works with:

  • Geographic coordinates (latitude/longitude)

  • Projected coordinates (meter-based grids like UTM)

  • Custom grids (model-specific coordinate systems)

The library relies on coordinate information from your data source (NetCDF attributes, GeoTIFF metadata, etc.).

Best practices

Check your CRS: Always verify that input locations use the same CRS as your river network

Use metadata: Store CRS information in your data files (NetCDF CF conventions, GeoTIFF tags)

Reproject when needed: Use tools like rasterio or pyproj to reproject coordinate data before using with earthkit-hydro

Document assumptions: Note which CRS you’re using in analysis scripts

See also