def test_coverage_union_reduce_axis():
# shape = (3, 2), all polygons - none of them overlapping
data = [[pygeos.box(i, j, i + 1, j + 1) for i in range(2)]
for j in range(3)]
actual = pygeos.coverage_union_all(data)
assert actual.shape == (2, )
actual = pygeos.coverage_union_all(data, axis=0) # default
assert actual.shape == (2, )
actual = pygeos.coverage_union_all(data, axis=1)
assert actual.shape == (3, )
actual = pygeos.coverage_union_all(data, axis=-1)
assert actual.shape == (3, )
def test_coverage_union_reduce_1dim(n):
"""
This is tested seperately from other set operations as it differs in two ways:
1. It expects only non-overlapping polygons
2. It expects GEOS 3.8.0+
"""
test_data = [
pygeos.box(0, 0, 1, 1),
pygeos.box(1, 0, 2, 1),
pygeos.box(2, 0, 3, 1),
]
actual = pygeos.coverage_union_all(test_data[:n])
# perform the reduction in a python loop and compare
expected = test_data[0]
for i in range(1, n):
expected = pygeos.coverage_union(expected, test_data[i])
assert pygeos.equals(actual, expected)
def union_or_combine(geometries, grid_size=None, op="union"):
"""First does a check for overlap of geometries according to STRtree
intersects. If any overlap, then will use union_all on all of them;
otherwise will return as a multipolygon.
If only one polygon is present, it will be returned in a MultiPolygon.
If coverage_union op is provided, geometries must be polygons and
topologically related or this will produce bad output or fail outright.
See docs for coverage_union in GEOS.
Parameters
----------
geometries : ndarray of single part polygons
grid_size : [type], optional (default: None)
provided to union_all; otherwise no effect
op : str, one of {'union', 'coverage_union'}
Returns
-------
MultiPolygon
"""
if not (pg.get_type_id(geometries) == 3).all():
print("Inputs to union or combine must be single-part geometries")
if len(geometries) == 1:
return pg.multipolygons(geometries)
tree = pg.STRtree(geometries)
left, right = tree.query_bulk(geometries, predicate="intersects")
# drop self intersections
ix = left != right
left = left[ix]
right = right[ix]
# no intersections, just combine parts
if len(left) == 0:
return pg.multipolygons(geometries)
# find groups of contiguous geometries and union them together individually
contiguous = np.sort(np.unique(np.concatenate([left, right])))
discontiguous = np.setdiff1d(np.arange(len(geometries), dtype="uint"),
contiguous)
groups = find_adjacent_groups(left, right)
parts = []
if op == "coverage_union":
for group in groups:
parts.extend(
pg.get_parts(pg.coverage_union_all(geometries[list(group)])))
else:
for group in groups:
parts.extend(
pg.get_parts(
pg.union_all(geometries[list(group)],
grid_size=grid_size)))
parts.extend(pg.get_parts(geometries[discontiguous]))
return pg.multipolygons(parts)
# state outer boundaries, NOT analysis boundaries
bnd_df = gp.read_feather(out_dir / "region_boundary.feather")
bnd = bnd_df.loc[bnd_df.id == "total"].geometry.values.data[0]
sarp_bnd = bnd_df.loc[bnd_df.id == "se"].geometry.values.data[0]
state_df = gp.read_feather(out_dir / "region_states.feather",
columns=["STATEFIPS", "geometry"])
states = state_df.STATEFIPS.unique()
sarp_state_df = gp.read_feather(out_dir / "sarp_states.feather",
columns=["STATEFIPS", "geometry"])
sarp_states = sarp_state_df.STATEFIPS.unique()
# Clip HUC4 areas outside state boundaries; these are remainder
state_merged = pg.coverage_union_all(state_df.geometry.values.data)
# find all that intersect but are not contained
tree = pg.STRtree(huc4_df.geometry.values.data)
intersects_ix = tree.query(state_merged, predicate="intersects")
contains_ix = tree.query(state_merged, predicate="contains")
ix = np.setdiff1d(intersects_ix, contains_ix)
outer_huc4 = huc4_df.iloc[ix].copy()
outer_huc4["km2"] = pg.area(outer_huc4.geometry.values.data) / 1e6
# calculate geometric difference, explode, and keep non-slivers
outer_huc4["geometry"] = pg.difference(outer_huc4.geometry.values.data,
state_merged)
outer_huc4 = explode(outer_huc4)
outer_huc4["clip_km2"] = pg.area(outer_huc4.geometry.values.data) / 1e6
