Never search neighbors or triangulate in latitude/longitude degrees

CHANGELOG.rst

@@ -7,11 +7,47 @@ Unreleased
 
 * added a ``py.typed`` marker so that type checkers use the inline type hints of ``grid-process`` (PEP 561)
 * added example notebooks to the documentation illustrating ``interp2poi`` and ``interp2grid`` with open data, with
-  their dependencies in the optional ``example`` dependency group
+  their dependencies in the optional ``example`` dependency group. Two of them are global: GFS 2 m temperature to
+  stations worldwide (compared with GHCN-hourly observations) and ERA5 2 m temperature to the IFS 0.1° grid
 * fixed ``interp2grid`` and ``interp2poi`` truncating reprojected coordinates when the grid coordinates are
   integers (e.g. an LV95 destination grid built with ``np.arange``), which gave wrong values or NaN
 * fixed ``create_dst_grid`` with ``topright`` and ``resolution``: the resolution is now exact and ``topright``
   a closed upper bound, instead of the grid spacing being stretched to end exactly on ``topright``
+* fixed ``interp2poi`` and ``interp2grid`` (outside of the regular grid interpolation) searching nearest neighbors
+  and triangulating (``linear``, ``cubic``) in latitude/longitude degrees, where a degree of longitude is shorter
+  than a degree of latitude (about 0.68 times in Switzerland). Distances are now always in meters: native
+  coordinates projected in meters are used even if latitude/longitude coordinates are present (e.g. LV95 grids),
+  and latitude/longitude grids are converted to Swiss LV95, or to earth-centered earth-fixed coordinates (ECEF) far
+  from Switzerland. Neighbors, IDW weights and ``linear``/``cubic`` results change slightly for grids that were
+  searched in latitude/longitude, including native LV95 grids with latitude/longitude coordinates
+* fixed the reprojection of grids in rotated pole (or latitude/longitude) on a sphere without datum, e.g. from a CF
+  grid mapping with ``earth_radius``: their latitudes and longitudes are now considered as WGS84 ones, as their
+  latitude/longitude coordinates usually are. The datum shift to Swiss coordinates (about 180 m) was left out.
+  ``parse_grid_mapping`` (and ``get_grid_crs``) now return such CF mappings directly on WGS84, without
+  ``pyproj.CRS.from_cf``, which took about 0.3 s for a rotated pole; other mappings parsed by ``from_cf`` are cached
+* added the support of global and other non-Swiss latitude/longitude grids by ``interp2poi`` and ``interp2grid``
+  (except ``linear``, ``linear_3D`` and ``cubic``, which raise an error), with nearest neighbor searches in ECEF
+  coordinates. The maximum distance of the destination to the LV95 central northing for using LV95 is set by the
+  new setting ``lv95_max_offset`` (environment variable ``GRID_PROCESS__lv95_max_offset``, default 700 km)
+* changed the methods with altitude, which no longer reproject to Swiss coordinates when the source grid or the
+  destination has another CRS projected in meters (e.g. UTM)
+* added an explicit error when the destination grid of ``interp2grid`` is unstructured, which is not supported
+* fixed ``interp2poi`` and ``interp2grid`` with latitude/longitude source grids whose longitude convention
+  (0..360 or -180..180) differs from the one of the POIs or destination grid: the source was sliced to the
+  wrong longitudes (wrong values in the generic path, e.g. for a global destination grid) and the regular grid
+  interpolation (``try_reg=True``) returned NaN. Global latitude/longitude grids are also interpolated across
+  their 360 degree seam. When slicing a latitude/longitude source grid, the longitude buffer is widened by
+  1 / cos(latitude) (as nearest neighbors are now searched in meters) and all longitudes are kept close to the
+  poles
+* changed the ``temp`` method of ``interp2poi``: POIs whose nearest grid points all have the same altitude (e.g.
+  close to the poles of a latitude/longitude grid, whose pole rows repeat the same point, or on flat orography)
+  use the fixed lapse rate fallback (as POIs far above or below their neighborhood) instead of raising an error
+* fixed ``create_dst_grid_from_src``: the destination grid now spans exactly the bounding box of the source domain
+  reprojected in the destination CRS (from native coordinates projected in meters when available), instead of the
+  reprojected corners of its latitude/longitude bounding box, which could be much larger (e.g. +80 km for ICON-CH2
+  in LV95) or miss parts of the domain (e.g. 28 km for IFS in LV95)
+* fixed ``set_grid_mapping`` with CF grid mappings holding numpy arrays or non-float64 numpy values (e.g. a
+  ``standard_parallel`` array read from a netCDF file), which raised a ``TypeError``
 
 1.0.0
 -----

doc/examples.rst

@@ -3,8 +3,8 @@ Examples
 ========
 
 The following notebooks illustrate the spatial interpolation functions of :mod:`grid_process.grid_interp` with open
-data from MeteoSwiss, ECMWF, Copernicus and swisstopo. Each one compares several interpolation methods visually and
-with a runtime benchmark.
+data from MeteoSwiss, ECMWF, Copernicus, swisstopo and NOAA. Each one compares several interpolation methods visually
+and with a runtime benchmark. The first four examples cover Switzerland, the last two the whole globe.
 
 The notebooks are rendered with the outputs of their last execution. Since open forecast data are only kept for a few
 days, re-running them retrieves more recent forecasts. To run them, install the extra dependencies with::
@@ -17,12 +17,12 @@ keep them between sessions, enable its cache once, e.g. in ``~/.config/earthkit/
     cache-policy: user
     user-cache-directory: /path/to/a/large/disk/earthkit-cache
 
-The ERA5-Land example additionally needs a free account on the
+The ERA5-Land and ERA5 examples additionally need a free account on the
 `Copernicus Climate Data Store <https://cds.climate.copernicus.eu>`_, with the API token in ``~/.cdsapirc`` and the
-licence of the dataset accepted once on its download page.
+licences of the datasets accepted once on their download pages.
 
-All data are open data under the CC BY 4.0 licence (MeteoSwiss, ECMWF, Copernicus Climate Change Service) or the
-open data terms of swisstopo. The data sources are credited in each notebook.
+All data are open data under the CC BY 4.0 licence (MeteoSwiss, ECMWF, Copernicus Climate Change Service), the
+open data terms of swisstopo, or in the public domain (NOAA). The data sources are credited in each notebook.
 
 .. toctree::
    :maxdepth: 1
@@ -31,3 +31,5 @@ open data terms of swisstopo. The data sources are credited in each notebook.
    examples/02_interp2poi_ifs_temperature
    examples/03_interp2grid_era5land_precipitation
    examples/04_interp2grid_valais_temperature
+   examples/05_interp2poi_gfs_global_temperature
+   examples/06_interp2grid_era5_global_temperature