shapegraph.py 文件源码

def point_projects_to_edges(self, point, distance_tolerance=0.01):
        """
        Project a point to graph edges considering specific distance tolerance.
        Note the tolerance is measured by great circle distance to point per se.
        :param point: a shapely Point instance or (lon, lat) tuple
        :param distance_tolerance: tolerance of distance in km
        :return: a list of projected edges, reversely sorted by offsets.
        """
        point_buffer = distance_to_buffer(distance_tolerance)
        p_buf = Point(point).buffer(point_buffer)
        projected_edges = []
        projected_segments = []
        major = self.major_component()
        for i in range(0, len(major)):
            line_index = major[i]
            line = self.geoms[line_index]
            if line.intersects(p_buf):
                cuts = self.line_cuts(line_index)
                if cuts is None:
                    continue
                for j in range(1, len(cuts)):
                    sinx = cuts[j - 1]
                    einx = cuts[j]
                    segment = line.coords[sinx:einx + 1]
                    ls = LineString(segment)
                    if ls.intersects(p_buf):
                        edge = self.edge_key(segment[0], segment[-1])
                        offset = ls.distance(Point(point))  # no buffer
                        projected_edges.append((edge, offset))
                        projected_segments.append(segment)
        result = sorted(projected_edges, key=lambda x: x[1], reverse=True)
        edges = list(set([i[0] for i in result]))
        return edges, projected_segments