diff --git a/src/snkit/network.py b/src/snkit/network.py index 202e664..491dab8 100644 --- a/src/snkit/network.py +++ b/src/snkit/network.py @@ -279,16 +279,23 @@ def round_geometries(network: Network, precision: int = 3) -> Network: return network -def split_multilinestrings(network: Network) -> Network: +def split_multilinestrings(network: Network, merge_parts: bool = False) -> Network: """ Create multiple edges from any MultiLineString edge Ensures that edge geometries are all LineStrings, duplicates attributes over any created multi-edges. + + Parameters + ---------- + merge_parts : default False + Merge parts of geometries if they are connected, before splitting to multiple edges """ edges = network.edges geom_col: str = geometry_column_name(edges) + if merge_parts: + edges.geometry = edges.geometry.apply(merge_multilinestring) split_edges = edges.explode(column=geom_col, ignore_index=True) geo_types = set(split_edges.geom_type) diff --git a/tests/test_init.py b/tests/test_init.py index af150e4..3ae6f77 100644 --- a/tests/test_init.py +++ b/tests/test_init.py @@ -642,7 +642,7 @@ def test_split_multilinestrings(): mls_coords = [ ( (0, 0), - (0, 1), + (0, 1.1), ), ( (1, 1), @@ -681,6 +681,64 @@ def test_split_multilinestrings(): assert list(split_network.edges.index.values) == list(range(4)) +def test_split_multilinestrings_merge(): + """Explode multilinestrings into linestrings - with parts merged if possible""" + + # point coordinates comprising three linestrings + mls_coords = [ + ( + (0, 0), + (0, 1), # should link to third part + ), + ( + (1, 1), + (2, 2), + (2, 1), + ), + ( + (0, 1), # should merge with first part + (-1, 1), + (-1, 2), + (-1, 0), + ), + ] + # point coordsinate comprising a single linestring + ls_coords = [(4, 0), (4, 1), (4, 2)] + + # make input network edges + edges = GeoDataFrame( + { + "data": ["MLS", "LS"], + "geometry": [MultiLineString(mls_coords), LineString(ls_coords)], + } + ) + multi_network = snkit.network.Network(edges=edges) + # check we have two rows (multilinestring and linestring) in the input network + assert len(multi_network.edges) == 2 + + # split and check we have three rows (the resulting linestrings) in the output network + split_network = snkit.network.split_multilinestrings(multi_network) + assert len(split_network.edges) == 4 + + # check data is replicated from multilinestring to child linestrings + assert list(split_network.edges["data"].values) == ["MLS"] * 3 + ["LS"] + + # check everything is reindexed + assert list(split_network.edges.index.values) == list(range(4)) + + # Check again, with merge_parts + split_network_merged = snkit.network.split_multilinestrings( + multi_network, merge_parts=True + ) + assert len(split_network_merged.edges) == 3 + + # check data is replicated from multilinestring to child linestrings + assert list(split_network_merged.edges["data"].values) == ["MLS"] * 2 + ["LS"] + + # check everything is reindexed + assert list(split_network_merged.edges.index.values) == list(range(3)) + + def test_link_nodes_to_edges_within(gap, bridged): """Nodes should link to edges within a distance, splitting the node at a new point if necessary.