Creating a polygon from a list of points¶

# Imports
import random

import folium
from scipy.spatial import ConvexHull


# Function to create a list of some random points
def randome_points(amount, LON_min, LON_max, LAT_min, LAT_max):

    points = []
    for _ in range(amount):
        points.append(
            (random.uniform(LON_min, LON_max), random.uniform(LAT_min, LAT_max))
        )

    return points


# Function to draw points in the map
def draw_points(map_object, list_of_points, layer_name, line_color, fill_color, text):

    fg = folium.FeatureGroup(name=layer_name)

    for point in list_of_points:
        fg.add_child(
            folium.CircleMarker(
                point,
                radius=1,
                color=line_color,
                fill_color=fill_color,
                popup=(folium.Popup(text)),
            )
        )

    map_object.add_child(fg)

# Function that takes a map and a list of points (LON,LAT tupels) and
# returns a map with the convex hull polygon from the points as a new layer


def create_convexhull_polygon(
    map_object, list_of_points, layer_name, line_color, fill_color, weight, text
):

    # Since it is pointless to draw a convex hull polygon around less than 3 points check len of input
    if len(list_of_points) < 3:
        return

    # Create the convex hull using scipy.spatial
    form = [list_of_points[i] for i in ConvexHull(list_of_points).vertices]

    # Create feature group, add the polygon and add the feature group to the map
    fg = folium.FeatureGroup(name=layer_name)
    fg.add_child(
        folium.vector_layers.Polygon(
            locations=form,
            color=line_color,
            fill_color=fill_color,
            weight=weight,
            popup=(folium.Popup(text)),
        )
    )
    map_object.add_child(fg)

    return map_object

def create_envelope_polygon(
    map_object, list_of_points, layer_name, line_color, fill_color, weight, text
):

    # Since it is pointless to draw a box around less than 2 points check len of input
    if len(list_of_points) < 2:
        return

    # Find the edges of box
    from operator import itemgetter

    list_of_points = sorted(list_of_points, key=itemgetter(0))
    x_min = list_of_points[0]
    x_max = list_of_points[len(list_of_points) - 1]

    list_of_points = sorted(list_of_points, key=itemgetter(1))
    y_min = list_of_points[0]
    y_max = list_of_points[len(list_of_points) - 1]

    upper_left = (x_min[0], y_max[1])
    upper_right = (x_max[0], y_max[1])
    lower_right = (x_max[0], y_min[1])
    lower_left = (x_min[0], y_min[1])

    edges = [upper_left, upper_right, lower_right, lower_left]

    # Create feature group, add the polygon and add the feature group to the map
    fg = folium.FeatureGroup(name=layer_name)
    fg.add_child(
        folium.vector_layers.Polygon(
            locations=edges,
            color=line_color,
            fill_color=fill_color,
            weight=weight,
            popup=(folium.Popup(text)),
        )
    )
    map_object.add_child(fg)

    return map_object