def find_valid_data_region(geobox, *sources_list):
# perform work in CRS of the output tile geobox
unfused = [[
dataset.extent.to_crs(geobox.crs) for dataset in tile.sources.item()
] for tile in sources_list]
# fuse the dataset extents within each source tile
tiles_extents = map(unary_union, unfused)
# find where (within the output tile) that all prerequisite inputs available
return unary_intersection([geobox.extent] + list(tiles_extents))
def test_unary_intersection():
box1 = geometry.box(10, 10, 30, 30, crs=geometry.CRS('EPSG:4326'))
box2 = geometry.box(15, 10, 35, 30, crs=geometry.CRS('EPSG:4326'))
box3 = geometry.box(20, 10, 40, 30, crs=geometry.CRS('EPSG:4326'))
box4 = geometry.box(25, 10, 45, 30, crs=geometry.CRS('EPSG:4326'))
box5 = geometry.box(30, 10, 50, 30, crs=geometry.CRS('EPSG:4326'))
box6 = geometry.box(35, 10, 55, 30, crs=geometry.CRS('EPSG:4326'))
inter1 = geometry.unary_intersection([box1])
assert bool(inter1)
assert inter1 == box1
inter2 = geometry.unary_intersection([box1, box2])
assert bool(inter2)
assert inter2.area == 300.0
inter3 = geometry.unary_intersection([box1, box2, box3])
assert bool(inter3)
assert inter3.area == 200.0
inter4 = geometry.unary_intersection([box1, box2, box3, box4])
assert bool(inter4)
assert inter4.area == 100.0
inter5 = geometry.unary_intersection([box1, box2, box3, box4, box5])
assert bool(inter5)
assert inter5.type == 'LineString'
assert inter5.length == 20.0
inter6 = geometry.unary_intersection([box1, box2, box3, box4, box5, box6])
assert not bool(inter6)
assert inter6.is_empty