Improve map to use points on higher zoom levels

[m-mohr]

From Caleb:

One thing I noticed is that it is very hard to see where the kenya/rwanda examples in low zoom level. One way to get around this is to generate pmtiles that are centroids at low zoom levels and polygons at high zoom levels:
Here's how I did it for GRW (I played with drop rate on the points a bit and visualized in QGIS)
tippecanoe --drop-densest-as-needed --drop-rate=2.5 --minimum-zoom=0 --maximum-zoom=9 --force -o solar_centroids.mbtiles solar_centroids_epsg4326.geojson
tippecanoe --minimum-zoom=9 -o solar.mbtiles solar_epsg4326.geojson
tile-join --force -o output.mbtiles solar.mbtiles solar_centroids.mbtiles
on the front end you can point a bubblelayer and vectorlayer (depending on library) at the same vector tile source

[m-mohr]

Working on it right now, the commands I've used so far:

1. Merge FTW datasets:
   fiboa convert ftw -o ftw.parquet
2. Compute centroids:
   ogr2ogr -sql "SELECT ST_Centroid(geometry) AS geometry, id, determination_datetime, dataset, license FROM ftw" -dialect sqlite ftw_centroid.parquet ftw.parquet
3. Create GeoJSON with polygons:
   ogr2ogr -t_srs EPSG:4326 ftw_sources.json ftw.parquet
4. Create GeoJSON with points/centroids:
   ogr2ogr -t_srs EPSG:4326 ftw_sources_centroid.json ftw_centroid.parquet
5. Create PMTiles with polygons:
   tippecanoe --drop-densest-as-needed --minimum-zoom=9 --force -o ftw_sources_lv9.pmtiles ftw_sources.json
6. Create PMTiles with points/centroids:
   tippecanoe --drop-densest-as-needed --minimum-zoom=0 --maximum-zoom=9 --force -o ftw_sources_centroids.pmtiles ftw_sources_centroid.json
7. Merge PMTiles files:
   tile-join --force -l "ftw_sources" -o ftw-sources.pmtiles ftw_sources_centroids.pmtiles ftw_sources_lv9.pmtiles

The tile-join doesn't really work for me yet, can't get the PMTiles to properly merge it seems.
I could load the separate PMTiles files on the map, but that's probably not what we want here given that others are already using the PMTiles file.