Boundaries layer features tagged maritime_boundary = 1 in error

[nvkelso]

• What did you see? Land boundaries are being tagged maritime_boundary = 1, like the USA-Canada country boundary, and the Idaho-Washington region boundary.
• What did you expect to see? Land boundaries should be tagged maritime_boundary = 0.
• What map location are you having problems with? https://tangrams.github.io/bubble-wrap/#8/47.874/-119.243.
  • Bad at zoom 8+ at OSM sourced zooms.
  • Natural Earth low zooms use different process and are fine (they are 0 and display correctly in Bubble Wrap).
• Screenshot?

[nvkelso]

Looking at the tile content in QGIS it seems the features are correctly in the tiles, but with the wrong property attributes (martime_boundary = 1 instead of 0):

Zoom 7 in QGIS at 512 px size:
https://tile.nextzen.org/tilezen/vector/v1/512/all/7/22/44.topojson?api_key=xyz

Zoom 8 in QGIS at 512 px size:
https://tile.nextzen.org/tilezen/vector/v1/512/all/8/44/88.topojson?api_key=xyz

[nvkelso]

Related:

• Gaza updates to src shapefile were the latest: Gaza Strip Border Issue #1257
• Prepare data S3 bucket error: import data shapefiles.tar.gz 404 #1479

[nvkelso]

The way I read the code we default to a maritime boundary unless the buffered land polygon intersects the feature and proves otherwise. @zerebubuth can you confirm that?

I suspect the buffered land polygon isn't included in RAWR tile export which means it's not available for the hit test. @zerebubuth can you confirm that please?

• https://github.com/tilezen/raw_tiles/blob/c7a042cd64a8b29ca3ab9919893c06bc37ecd3b7/raw_tiles/source/__init__.py#L6-L12

To whit, there should be an integration-test for this functionality but it's MIA. I'll add one but since CI in this repo is based on Postgres connection I expect it to pass here and then we'd need to run it separately on the RAWR tile build results manually.

===

The boundaries YAML logic just looks to the line's data attribute:

vector-datasource/yaml/boundaries.yaml

Line 7 in b1c43fd

maritime_boundary: {col: maritime_boundary}

There's some setup:

vector-datasource/data/shapefile_schema/buffered_land.sql

Lines 2 to 7 in 81d415e

	CREATE TABLE "buffered_land" (
	gid serial,
	"featurecla" varchar(32),
	"scalerank" numeric);
	ALTER TABLE "buffered_land" ADD PRIMARY KEY (gid);
	SELECT AddGeometryColumn('','buffered_land','the_geom','3857','MULTIPOLYGON',2);

And a lot of post processing in the transforms section:

vector-datasource/vectordatasource/transform.py

Lines 1717 to 1861 in dc7655f

	def admin_boundaries(ctx):
	"""
	Given a layer with admin boundaries and inclusion polygons for
	land-based boundaries, attempts to output a set of oriented
	boundaries with properties from both the left and right admin
	boundary, and also cut with the maritime information to provide
	a `maritime_boundary: True` value where there's overlap between
	the maritime lines and the admin boundaries.
	Note that admin boundaries must alread be correctly oriented.
	In other words, it must have a positive area and run counter-
	clockwise around the polygon for which it is an outer (or
	clockwise if it was an inner).
	"""
	feature_layers = ctx.feature_layers
	zoom = ctx.nominal_zoom
	base_layer = ctx.params.get('base_layer')
	assert base_layer, 'Parameter base_layer missing.'
	start_zoom = ctx.params.get('start_zoom', 0)
	layer = None
	# don't start processing until the start zoom
	if zoom < start_zoom:
	return layer
	layer = _find_layer(feature_layers, base_layer)
	if layer is None:
	return None
	# layer will have polygonal features for the admin
	# polygons and also linear features for the maritime
	# boundaries. further, we want to group the admin
	# polygons by their kind, as this will reduce the
	# working set.
	admin_features = defaultdict(list)
	maritime_features = list()
	new_features = list()
	# Sorting here so that we have consistent ordering of left/right side
	# on boundaries.
	sorted_layer = sorted(layer['features'], key=lambda f: f[1]['id'])
	for shape, props, fid in sorted_layer:
	dims = _geom_dimensions(shape)
	kind = props.get('kind')
	maritime_boundary = props.get('maritime_boundary')
	# the reason to use this rather than compare the
	# string of types is to catch the "multi-" types
	# as well.
	if dims == _LINE_DIMENSION and kind is not None:
	admin_features[kind].append((shape, props, fid))
	elif dims == _POLYGON_DIMENSION and maritime_boundary:
	maritime_features.append((shape, {'maritime_boundary': False}, 0))
	# there are separate polygons for each admin level, and
	# we only want to intersect like with like because it
	# makes more sense to have Country-Country and
	# State-State boundaries (and labels) rather than the
	# (combinatoric) set of all different levels.
	for kind, features in admin_features.iteritems():
	num_features = len(features)
	envelopes = [g[0].envelope for g in features]
	for i, feature in enumerate(features):
	boundary, props, fid = feature
	prop_id = props['id']
	envelope = envelopes[i]
	# intersect with *preceding* features to remove
	# those boundary parts. this ensures that there
	# are no duplicate parts.
	for j in range(0, i):
	cut_shape, cut_props, cut_fid = features[j]
	# don't intersect with self
	if prop_id == cut_props['id']:
	continue
	cut_envelope = envelopes[j]
	if envelope.intersects(cut_envelope):
	try:
	boundary = boundary.difference(cut_shape)
	except shapely.errors.TopologicalError:
	# NOTE: we have gotten errors Topological errors here
	# that look like:
	# TopologicalError: This operation could not be
	# performed. Reason: unknown"
	pass
	if boundary.is_empty:
	break
	# intersect with every *later* feature. now each
	# intersection represents a section of boundary
	# that we want to keep.
	for j in range(i+1, num_features):
	cut_shape, cut_props, cut_fid = features[j]
	# don't intersect with self
	if prop_id == cut_props['id']:
	continue
	cut_envelope = envelopes[j]
	if envelope.intersects(cut_envelope):
	inside, boundary = _intersect_cut(boundary, cut_shape)
	inside = _linemerge(inside)
	if not inside.is_empty:
	new_props = _merge_left_right_props(props, cut_props)
	new_props['id'] = props['id']
	_make_joined_name(new_props)
	new_features.append((inside, new_props, fid))
	if boundary.is_empty:
	break
	# anything left over at the end is still a boundary,
	# but a one-sided boundary to international waters.
	boundary = _linemerge(boundary)
	if not boundary.is_empty:
	new_props = props.copy()
	_make_joined_name(new_props)
	new_features.append((boundary, new_props, fid))
	# use intracut for maritime, but it intersects in a positive
	# way - it sets the tag on anything which intersects, whereas
	# we want to set maritime where it _doesn't_ intersect. so
	# we have to flip the attribute afterwards.
	cutter = _Cutter(maritime_features, None,
	'maritime_boundary', 'maritime_boundary',
	_LINE_DIMENSION, _intersect_cut)
	for shape, props, fid in new_features:
	cutter.cut(shape, props, fid)
	# flip the property, so define maritime_boundary=yes where
	# it was previously unset and remove maritime_boundary=no.
	for shape, props, fid in cutter.new_features:
	maritime_boundary = props.pop('maritime_boundary', None)
	if maritime_boundary is None:
	props['maritime_boundary'] = True
	layer['features'] = cutter.new_features
	return layer