fix(maps): france_regions.geojson generated with the notebook, from natural earth data

[qleroy]

Following #26995, and to fix the countries_custom/france_regions.geojson added in #25676,
I propose to generate france_regions.geojson from the data provided department-wise by Natural Earth Data
but that can be merged together into their parent division, i.e. regions.
The geopandas dissolve function can do just that and the mapping departments=>regions comes from the ISO 3166-2 FR norm

SUMMARY

The previous france_regions.geojson ,while it was generated from a solid source (IGN BD TOPO), is large (12MB) compared to other files and provided in the incorrect projection (EPSG 2154 instead of EPSG 4326 / WGS 84), resulting in a buggy display in Superset while using the Country Map plugin.

All files from Natural Earth Data are provided with the EPSG 4326 / WSG 84 (source) and it is the projection understood by the Country Map plugin as its current implementation.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

In the notebook

In Superset

Most relevant bit of code in the notebook:

france_regions = france_copy.copy()
# Define the mapping from the departments to their parent division
# i.e. from departments to regions
# Source: https://www.iso.org/obp/ui/#iso:code:3166:FR
dep_to_reg = {
    "FR-01": "FR-ARA",
    "FR-02": "FR-HDF",
    "FR-03": "FR-ARA",
    "FR-04": "FR-PAC",
    "FR-05": "FR-PAC",
    "FR-06": "FR-PAC",
    "FR-07": "FR-ARA",
    "FR-08": "FR-GES",
    "FR-09": "FR-OCC",
    "FR-10": "FR-GES",
    "FR-11": "FR-OCC",
    "FR-12": "FR-OCC",
    "FR-13": "FR-PAC",
    "FR-14": "FR-NOR",
    "FR-15": "FR-ARA",
    "FR-16": "FR-NAQ",
    "FR-17": "FR-NAQ",
    "FR-18": "FR-CVL",
    "FR-19": "FR-NAQ",
    "FR-21": "FR-BFC",
    "FR-22": "FR-BRE",
    "FR-23": "FR-NAQ",
    "FR-24": "FR-NAQ",
    "FR-25": "FR-BFC",
    "FR-26": "FR-ARA",
    "FR-27": "FR-NOR",
    "FR-28": "FR-CVL",
    "FR-29": "FR-BRE",
    "FR-2A": "FR-20R",
    "FR-2B": "FR-20R",
    "FR-30": "FR-OCC",
    "FR-31": "FR-OCC",
    "FR-32": "FR-OCC",
    "FR-33": "FR-NAQ",
    "FR-34": "FR-OCC",
    "FR-35": "FR-BRE",
    "FR-36": "FR-CVL",
    "FR-37": "FR-CVL",
    "FR-38": "FR-ARA",
    "FR-39": "FR-BFC",
    "FR-40": "FR-NAQ",
    "FR-41": "FR-CVL",
    "FR-42": "FR-ARA",
    "FR-43": "FR-ARA",
    "FR-44": "FR-PDL",
    "FR-45": "FR-CVL",
    "FR-46": "FR-OCC",
    "FR-47": "FR-NAQ",
    "FR-48": "FR-OCC",
    "FR-49": "FR-PDL",
    "FR-50": "FR-NOR",
    "FR-51": "FR-GES",
    "FR-52": "FR-GES",
    "FR-53": "FR-PDL",
    "FR-54": "FR-GES",
    "FR-55": "FR-GES",
    "FR-56": "FR-BRE",
    "FR-57": "FR-GES",
    "FR-58": "FR-BFC",
    "FR-59": "FR-HDF",
    "FR-60": "FR-HDF",
    "FR-61": "FR-NOR",
    "FR-62": "FR-HDF",
    "FR-63": "FR-ARA",
    "FR-64": "FR-NAQ",
    "FR-65": "FR-OCC",
    "FR-66": "FR-OCC",
    "FR-67": "FR-GES",
    "FR-68": "FR-GES",
    "FR-69": "FR-ARA",
    "FR-70": "FR-BFC",
    "FR-71": "FR-BFC",
    "FR-72": "FR-PDL",
    "FR-73": "FR-ARA",
    "FR-74": "FR-ARA",
    "FR-75": "FR-IDF",
    "FR-76": "FR-NOR",
    "FR-77": "FR-IDF",
    "FR-78": "FR-IDF",
    "FR-79": "FR-NAQ",
    "FR-80": "FR-HDF",
    "FR-81": "FR-OCC",
    "FR-82": "FR-OCC",
    "FR-83": "FR-PAC",
    "FR-84": "FR-PAC",
    "FR-85": "FR-PDL",
    "FR-86": "FR-NAQ",
    "FR-87": "FR-NAQ",
    "FR-88": "FR-GES",
    "FR-89": "FR-BFC",
    "FR-90": "FR-BFC",
    "FR-91": "FR-IDF",
    "FR-92": "FR-IDF",
    "FR-93": "FR-IDF",
    "FR-94": "FR-IDF",
    "FR-95": "FR-IDF",
    "FR-GF": "FR-GF",
    "FR-MQ": "FR-MQ",
    "FR-GP": "FR-GP",
    "FR-RE": "FR-RE",
    "FR-YT": "FR-YT",
}
# Apply the mapping departments => regions
france_regions["iso_3166_2_region"] = france_regions['iso_3166_2'].apply(lambda x: dep_to_reg[x])
# Merge the departments together 
# https://geopandas.org/en/stable/docs/user_guide/aggregation_with_dissolve.html
france_regions = france_regions.dissolve(by='iso_3166_2_region')
# Fix the label
france_regions['iso_3166_2'] = france_regions['iso_3166_2'].index
# Fix the name
france_regions['name'] = france_regions['region']
france_regions.plot()

TESTING INSTRUCTIONS

Run the notebook to generate the new france_regions.geojson

ADDITIONAL INFORMATION

• Has associated issue: France Region file too large and in EPSG 2154 projection instead of EPSG 4326 (WGS 84) #26846
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[rusackas]

Looks good to me! Tested it in the notebook, and all seems well.

I have another PR with a notebook change... i hope these things can be merged together like any other code 😅