Source code for sertit.geometry

```# -*- coding: utf-8 -*-
# Copyright 2024, SERTIT-ICube - France, https://sertit.unistra.fr/
# This file is part of sertit-utils project
#     https://github.com/sertit/sertit-utils
#
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#
# Unless required by applicable law or agreed to in writing, software
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
"""
Geometry tools

You can use this only if you have installed sertit[full] or sertit[vectors]
"""
import logging

import numpy as np
from shapely.errors import GeometryTypeError
from tqdm import tqdm

from sertit.types import AnyPolygonType

try:
import geopandas as gpd
from shapely import ops
from shapely.geometry import Polygon, box
except ModuleNotFoundError as ex:
raise ModuleNotFoundError(
"Please install 'geopandas' to use the rasters package."
) from ex

from sertit import vectors
from sertit.logs import SU_NAME

LOGGER = logging.getLogger(SU_NAME)

[docs]
def from_polygon_to_bounds(polygon: AnyPolygonType) -> (float, float, float, float):
"""
Convert a :code:`shapely.polygon` to its bounds, sorted as :code:`left, bottom, right, top`.

.. code-block:: python

>>> poly = Polygon(((0., 0.), (0., 1.), (1., 1.), (1., 0.), (0., 0.)))
>>> from_polygon_to_bounds(poly)
(0.0, 0.0, 1.0, 1.0)

Args:
polygon (MultiPolygon): polygon to convert

Returns:
(float, float, float, float): left, bottom, right, top
"""
left = polygon.bounds[0]  # xmin
bottom = polygon.bounds[1]  # ymin
right = polygon.bounds[2]  # xmax
top = polygon.bounds[3]  # ymax

assert left < right
assert bottom < top

return left, bottom, right, top

[docs]
def from_bounds_to_polygon(
left: float, bottom: float, right: float, top: float
) -> Polygon:
"""
Convert the bounds to a :code:`shapely.polygon`.

.. code-block:: python

>>> poly = from_bounds_to_polygon(0.0, 0.0, 1.0, 1.0)
>>> print(poly)
'POLYGON ((1 0, 1 1, 0 1, 0 0, 1 0))'

Args:
left (float): Left coordinates
bottom (float): Bottom coordinates
right (float): Right coordinates
top (float): Top coordinates

Returns:
Polygon: Polygon corresponding to the bounds

"""
return box(min(left, right), min(top, bottom), max(left, right), max(top, bottom))

[docs]
def get_wider_exterior(vector: gpd.GeoDataFrame) -> gpd.GeoDataFrame:
"""
Get the wider exterior of a MultiPolygon as a Polygon

Args:
vector (gpd.GeoDataFrame): Polygon to simplify

Returns:
vector: gpd.GeoDataFrame: Wider exterior
"""
vector = vector.explode(index_parts=True)

# Get the footprint max (discard small holes stored in other polygons)
wider = vector[vector.area == np.max(vector.area)]

# Only select the exterior of this footprint(sometimes some holes persist)
if not wider.empty:
poly = Polygon(list(wider.exterior.iat[0].coords))
wider = gpd.GeoDataFrame(geometry=[poly], crs=wider.crs)

# Resets index as we only got one polygon left which should have index 0
wider.reset_index(inplace=True)

return wider

[docs]
def make_valid(gdf: gpd.GeoDataFrame, verbose=False) -> gpd.GeoDataFrame:
"""
Repair geometries from a dataframe.

Args:
gdf (gpd.GeoDataFrame): GeoDataFrame to repair
verbose (bool): Verbose invalid geometries

Returns:
gpd.GeoDataFrame: Repaired geometries
"""
try:
geos_logger = logging.getLogger("shapely.geos")
previous_level = geos_logger.level
if verbose:
logging.debug("Invalid geometries:\n" f"\t{gdf[~gdf.is_valid]}")
else:
geos_logger.setLevel(logging.CRITICAL)

# Discard self-intersection and null geometries
from shapely.validation import make_valid

gdf.geometry = gdf.geometry.apply(make_valid)

if not verbose:
geos_logger.setLevel(previous_level)
except ImportError:
import shapely

LOGGER.warning(
f"make_valid not available in shapely (version {shapely.__version__} < 1.8). "
f"The obtained vector may be broken !"
)

return gdf

[docs]
def simplify_footprint(
footprint: gpd.GeoDataFrame, resolution: float, max_nof_vertices: int = 50
) -> gpd.GeoDataFrame:
"""
Simplify footprint.

Set a number of maximum vertices and this function will try to simplify the footprint to have less than this number of vertices.
The tolerance will grow to try to respect this number of vertices.

This function will loop over a number of pixels of tolerence [1, 2, 4, 8, 16, 32, 64] (tolerance of gpd.simplify == resolution * tol_pix)
If in the end, the number of vertices is still too high, a warning will be emitted.

Args:
footprint (gpd.GeoDataFrame): Footprint to be simplified
resolution (float): Corresponding resolution
max_nof_vertices (int): Maximum number of vertices of the wanted footprint

Returns:
gpd.GeoDataFrame: Simplified footprint
"""
# Number of pixels of tolerance
tolerance = [1, 2, 4, 8, 16, 32, 64]

# Process only if given footprint is too complex (too many vertices)
def simplify_geom(value):
nof_vertices = len(value.exterior.coords)
if nof_vertices > max_nof_vertices:
for tol in tolerance:
# Simplify footprint
value = value.simplify(
tolerance=tol * resolution, preserve_topology=True
)

# Check if OK
nof_vertices = len(value.exterior.coords)
if nof_vertices <= max_nof_vertices:
break
return value

footprint = footprint.explode(index_parts=True)
footprint.geometry = footprint.geometry.apply(simplify_geom)

return footprint

[docs]
def fill_polygon_holes(
gpd_results: gpd.GeoDataFrame, threshold: float = None
) -> gpd.GeoDataFrame:
"""
Fill holes over a given threshold on the hole area (in meters) for all polygons of a GeoDataFrame.
If the threshold is set to None, every hole is filled.

Args:
gpd_results (gpd.GeoDataFrame): Geodataframe filled whith drilled polygons
threshold (float): Holes area threshold, in meters. If set to None, every hole is filled.

Returns:
gpd.GeoDataFrame: GeoDataFrame with filled holes
"""

def _fill_polygon(polygon: Polygon, threshold: float = None):
"""
Function used in apply in fill_polygon_holes
"""
if threshold is not None:
if threshold > 0 and len(polygon.interiors) > 0:
new_interiors = list(polygon.interiors)
for interior in polygon.interiors:
interior_poly = Polygon(np.array(interior.coords))
if interior_poly.area < threshold:
new_interiors.remove(interior)
return Polygon(polygon.exterior, new_interiors)
else:
return polygon
else:
return Polygon(polygon.exterior)

# Ensure the geometries are valid
gpd_results = make_valid(gpd_results)

# Check if vector is projected, if not convert it
with vectors.utm_crs(gpd_results) as utm_results:
# Explode the multipolygons
utm_results = utm_results.explode(index_parts=False)

# Keep only the exterior
tqdm.pandas(desc="Processing objects")
utm_results.geometry = utm_results.geometry.progress_apply(
_fill_polygon, args=(threshold,)
)

# Dissolve and explode to remove polygons in polygons
utm_results = utm_results.dissolve()
gpd_results = utm_results.explode(index_parts=False)

# Write back to file
return gpd_results

[docs]
def split(polygons: gpd.GeoDataFrame, splitter: gpd.GeoDataFrame):
"""
Split polygons with polygons

Args:
polygons (gpd.GeoDataFrame): Polygons to split
splitter (gpd.GeoDataFrame): Splitter to split the polygons

Returns:
gpd.GeoDataFrame: Split GeoDataFrame
"""
out = polygons.geometry
for _, split in splitter.iterrows():
# Compute the boundary of the splitter polygon (to get a LineString)
boundary = split.geometry.boundary

# Explode to prevent FeatureCollections
try:
# LineStrings
out = out.map(lambda geom: ops.split(geom, boundary).geoms).explode()
except GeometryTypeError:
# MultiLineStrings
for line in boundary.geoms:
out = out.map(lambda geom: ops.split(geom, line).geoms).explode()

return gpd.GeoDataFrame(geometry=out.explode(), crs=polygons.crs)

```