Separate landcover kinds from landuse layer into new layer

[nvkelso]

The landuse layer has a mix of landcover and landuse in it now. Let's consider separating many of these kinds into their own layer, when they are more natural and less cultural / urban.

Related to #1885 and #1905. Basically at low zooms you want generalized globally consistent landcover, but starting at zoom 13 (modify to taste, but there are a few configs) you want specific highly detailed landcover.

WARNING: This is a breaking SemVer change.

These are generic landcover layers to move over (as kind_detail, with new kind in parenthetical):

• natural: wetland (wetland)
• natural: mud (wetland) - this seems odd, isn't is mostly under water?
• landuse: forest – but not all the managed "National Forests" (forest)
• natural: forest – but not all the managed "National Forests" (forest)
• landuse: wood – but not all the managed "National Forests" (forest)
• natural: wood – but not all the managed "National Forests" (forest)
• natural: scrub (scrub) – this is mapped to grassland now, but that's in error
• natural: heath (scrub) – this is mapped to grassland now, but that's in error
• landuse: grass (grassland)
• natural: grassland (grassland)
• landuse: meadow (grassland) - these sometimes have names
• natural: desert (desert)
• natural: bare_rock (desert) - should this be barren?
• natural: sand (desert) - should this be barren?
• natural: shingle (barren)
• natural: scree (barren)
• natural: stone (barren)
• natural: rock (barren)
• natural: glacier (glacier)
• landuse: farm (farmland)
• landuse: farmland (farmland)
• landuse: rural (rural)

These are funny line features that should also move over:

• natural: tree_row
• barrier: hedge (there may be special handling for barrier lines to bring over?)

These should perhaps stay in the landuse layer, as they all aggregate to urban_area to provide continuity with NE urban_area at low zooms (consider the same kind/kind_detail mapping change as above):

• landuse: urban (urban_area)
• landuse: residential (urban_area)
• landuse: industrial (urban_area)
• landuse: commercial (urban_area)

These are very detailed features so would remain in landuse layer:

• natural: beach - this is because tagging often includes beach "parks"

We also do a fair bit or remapping of landuse values at lower zooms:

• https://github.com/tilezen/vector-datasource/blob/master/queries.yaml#L347-L427

So let's set the kind to the remapped value, and the kind_detail to the existing values.

We'll want to migrate some of those over to the new layer.

We perform a landuse_kind intercut, which we may also want to provide as lancover_kind on a new layer? This is expensive.

• https://github.com/tilezen/vector-datasource/blob/master/queries.yaml#L1695-L1701

We also do generalization, which we'd want to apply to the new layer:

• https://github.com/tilezen/vector-datasource/blob/master/queries.yaml#L1747-L1815

We also want to generate label placements the same way as for landuse now:

• https://github.com/tilezen/vector-datasource/blob/master/queries.yaml#L840-L850

There are probably a few other transforms we'd want to pickup from the queries.yaml, so have another look.

[nvkelso]

This should be done after #1926 is merged, in dev cycle of 2.0 release.