The ocean layer (table osm_ocean_polygon insert by `make import-data`) is made from squares that have a 10m buffer.
This creates extra geometry in vector tiles as:
Union of full ocean squares should decrease the size of the water layer.
there are 8042 polygons (squares, 5 points, more then 100km<sup>2</sup>), which was reduced to 22 polygons - 1184kB vs 40kB respectively.
In mbtiles should be the size reduction even more significant, due to the creation of more polygons based on a 10m buffer of each square.
Move materialized view creation from the tools repo.
This PR should be merged before the https://github.com/openmaptiles/openmaptiles-tools/pull/115
Merge the other PR shortly after this one to avoid doing the same work twice - first creating simplified table, then dropping it and recreating them as materialized views.
Seems like etl and mapping diagrams have been neglected
for a long time. Now it regenerates the files and places
them in the source dir.
This PR also fixes two broken files:
* layers/aerodrome_label/mapping_diagram.png
* layers/housenumber/mapping_diagram.png
They were generated using the newest tools version with the fix
https://github.com/openmaptiles/openmaptiles-tools/pull/65
