Sentinel2 RGB chips over BENELUX with JRC GHSL Population Density 2015 for Learning with Label Proportions

Region of Interest (ROI) is comprised of the Belgium, the Netherlands and Luxembourg

We use the communes adminitrative division which is standardized across Europe by EUROSTAT at:
https://ec.europa.eu/eurostat/web/gisco/geodata/reference-data/administrative-units-statistical-units
This is roughly equivalent to the notion municipalities in most countries.

From the link above, communes definition are taken from COMM_RG_01M_2016_4326.shp and country borders
are taken from NUTS_RG_01M_2021_3035.shp.

images: Sentinel2 RGB from 2020-01-01 to 2020-31-12
        filtered out pixels with clouds acoording to QA60 band following the example
        given in GEE dataset info page at:
        see https://developers.google.com/earth-engine/datasets/catalog/COPERNICUS_S2_SR_HARMONIZED

        see also https://github.com/rramosp/geetiles/blob/main/geetiles/defs/sentinel2rgbmedian2020.py

labels: Global Human Settlement Layers, Population Grid 2015

        labels range from 0 to 31, with the following meaning:
           label value     original value in GEE dataset
           0               0
           1               1-10
           2               11-20
           3               21-30
           ...
           31              >=291 

        see https://developers.google.com/earth-engine/datasets/catalog/JRC_GHSL_P2016_POP_GPW_GLOBE_V1

        see also https://github.com/rramosp/geetiles/blob/main/geetiles/defs/humanpop2015.py

_aschips.geojson the image chips geometries along with label proportions
for easy visualization with QGIS, GeoPandas, etc.

_communes.geojson the communes geometries with their label prortions
for easy visualization with QGIS, GeoPandas, etc.

splits.csv contains two splits of image chips in train, test, val
- with geographical bands at 45° angles in nw-se direction
- the same as above reorganized to that all chips within the same
commune fall within the same split.

data/ a pickle file for each image chip containing a dict with
- the 100x100 RGB sentinel 2 chip image
- the 100x100 chip level lavels
- the label proportions of the chip
- the aggregated label proportions of the commune the chip belongs to