What’s New

v0.2.3 (06 January 2019)

A minor release of the salem package with small bugfixes and a couple of enhancements. This will be the last release to support python 2.


  • new extent_as_polygon() method, which creates a polygon outlining the contours of a Grid.
  • minimal support for MetUm rotated grid files (open_metum_dataset()), still experimental (PR117).

Bug fixes

  • the xarray accessor method roi() now preserves encoding (GH109). By Johannes Landmann
  • fixed a bug in geogrid_simulator that would occur if stand_lon and ref_lon were not set to the same value (a strange idea tbh)

v0.2.2 (21 June 2018)

A long overdue minor release of the salem package. It contains several enhancements and bugfixes.


  • transform_geopandas() can now handle grid to proj transformations.
  • Thw WRF vertical interpolation methods now accept a fill_value kwarg which is np.NaN per default but can be set to ‘extrapolate’ if needed.
  • New reduce() function, useful to aggregate structured high-res grids to lower-res grids (Shape to raster – subgrid)
  • new to_geometry() method, useful to compute precise vector to raster masks (TODO: example showing its use)
  • new projection for WRF files: polar stereographic
  • one can now add a scale bar to maps (see set_scale_bar())
  • google static maps now support the scale kwarg for higher resolution images (PR91). By tbridel
  • each salem version is now pinned to a certain commit of the sample-data repository. This is more robust and will avoid future tests to fail for the wrong reasons.
  • accessor’s roi method now accepts an other kwarg to fill masked values with something else than Nan (PR96). By Schlump

Bug fixes

  • the cache directory is also updated when the pandas version changes (GH74)
  • small bugfixes in the projections and warning handling
  • PRESSURE variable was given in Pa, not hPa. This is corrected now.
  • Small bugfixes in exotic WRF diag variables indexing
  • Corrected a bug in proj_to_cartopy where the spherical parameters were silently ignored. Cartopy maps on WRF domains are now perfect!
  • Grid.ij_to_crs should now handle non numpy arrays too
  • Corrected an internal bug with latest xarray version (PR97). Users will have to update to latest xarray version (v0.10+).
  • Added new coordinate names to be understood by salem (GH100).

v0.2.1 (07 February 2017)

Minor release containing a couple of enhancements and deprecations, but mostly fixes for bugs and for the recent xarray and matplotlib upgrades.


  • the corner, ul_corner, and ll_corner kwargs to grid initialisation have been deprecated in favor of the more explicit x0y0.
  • the Grid attribue order is now called origin, and can have the values "lower-left" or "upper-left"
  • salem.open_xr_dataset now succeeds if and only if the grid is understood by salem. This makes more sense, as unexpected errors should not be silently ignored


  • new open_mf_wrf_dataset() function
  • new deacc method added to DataArrayAccessors By SiMaria <https://github.com/SiMaria>
  • new Map.transform() method to make over-plotting easier (experimental)
  • new all_touched argument added to Grid.region_of_interest() to pass through to rasterio.features.rasterize, tweaking how grid cells are included in the region of interest. By Daniel Rothenberg
  • new lookup_transform() projection transform
  • Grid objects now have a decent __repr__
  • new serialization methods for grid: to_dict, from_dict, to_json, from_json.

Bug fixes

  • grid.transform() now works with non-numpy array type
  • transform_geopandas() won’t do inplace operation per default anymore
  • fixed bugs to prepare for upcoming xarray v0.9.0
  • setup.py makes cleaner version strings for development versions (like xarray’s)
  • joblib’s caching directory is now “environment dependant” in order to avoid conda/not conda mismatches, and avoid other black-magic curses related to caching.
  • fixed a bug with opening geo_em files using xarray or open_wrf_dataset
  • various bug fixes and enhancements to the graphics (including the relocation of testing baseline images to the demo repo)

v0.2.0 (08 November 2016)

Salem is now released under a 3-clause BSD license.


  • New wrf_zlevel() and wrf_plevel() functions for vertical interpolation
  • Salem can now plot on cartopy’s maps thanks to a new proj_to_cartopy() function.
  • Doc improvements
  • New diagnostic variable: ‘WS’

v0.1.1 (27 October 2016)


  • Some doc improvements
  • New ds keyword to the accessors subset() and roi() methods

Bug fixes

  • Natural Earth file lr (low-res) now shipped with sample-data, mr and hr can still be downloaded if needed
  • Remove use to deprecated rasterio.drivers()
  • GeoNetCDF files without time variable should now open without error

v0.1.0 (22 October 2016)

Big refactoring (PR15), partly backwards incompatible (mostly renaming). Improved xarray accessors, WRF tools, merged Cleo into the codebase, added a first draft of documentation.

v0.0.9 (22 October 2016)

Initial release.