geopandas

Geopandas uses shapely geometry objects and it can do plot, spatial join

This is an example of loading shapely polygons from a numpy array.

The shapely polygons are further loaded to pandas and geopandas.

geopandas then plots the shape.

import pandas as pd

from shapely.geometry import Polygon

import matplotlib.pyplot as plt

#polygon coordinates x1,y1, x2,y2, ...xn,yn, x1,y1

polygons=[

          [[0,0], [10,0], [10,10], [0,10], [0,0]],

          [[5,5], [20,5], [20,20], [5,20], [5,5]],

         ]

#convert from array to polygon objects

polygons = [Polygon(i) for i in polygons] 

#load polybon objects to pandas

df_polygons = pd.DataFrame(polygons, columns=['Poly'])

#convert pandas dataframe to geopandas dataframe and indicate the column of geometry object

gdf_polygons = gp.GeoDataFrame(

    df_polygons,

    geometry='Poly',

    crs='epsg:28355',

)

#simply plot all the geometry objects

gdf_polygons.plot(figsize=(5,5))

#can also plot to an matplotlib ax

#so as to combine with other plots

fig, ax = plt.subplots(1,1,figsize=(5,5))

gdf_polygons.plot(ax=ax)

plt.show()

The shapley geometry objects can be loaded from the string format directly as well

just use the wkt functions to intantiate the objects from string

the geopandas plot function can take matplotlib ax as a paramter so can overlap the plot with other plots

import pandas as pd

from shapely.geometry import Polygon, LineString, Point

import shapely.wkt as wkt

import matplotlib.pyplot as plt

#geometry objects in string format

geometry=[

          'Polygon((0 0, 10 0, 10 10, 0 10, 0 0))',

          'Polygon((5 5, 20 5, 20 20, 5 20, 5 5))',

          'LineString(0 20, 20 0)',

          'Point(30 30)',

         ]

#load polybon objects to pandas

df = pd.DataFrame(geometry, columns=['geom'])

df['geom'] = df['geom'].apply(lambda x: wkt.loads(x))

#convert pandas dataframe to geopandas dataframe and indicate the column of geometry object

gdf = gp.GeoDataFrame(

    df,

    geometry='geom',

    crs='epsg:28355',

)

#simply plot all the geometry objects

gdf.plot(figsize=(5,5))

Finally spatial join (sjoin) is handy to check if geometry objects intersect/contain with others.

The join type can be inner, left, right

import pandas as pd

from shapely.geometry import Polygon, LineString, Point

import shapely.wkt as wkt

import matplotlib.pyplot as plt

#geometry objects in string format

geometry=[

          'Polygon((0 0, 10 0, 10 10, 0 10, 0 0))',

          'Polygon((5 5, 20 5, 20 20, 5 20, 5 5))',

         ]

#load polybon objects to pandas

df = pd.DataFrame(geometry, columns=['geom'])

df['geom'] = df['geom'].apply(lambda x: wkt.loads(x))

#convert pandas dataframe to geopandas dataframe and indicate the column of geometry object

gdf = gp.GeoDataFrame(

    df,

    geometry='geom',

    crs='epsg:28355',

)

gdf1 = gdf.loc[[True, False]]

gdf2 = gdf.loc[[False, True]]

gdf_joined = gp.sjoin(

    gdf1,

    gdf2,

    how='inner',

    op='intersects', #{‘intersects’, ‘contains’, ‘within’}

)

fig, ax = plt.subplots(1,1,figsize=(5,5))

gdf1.plot(ax=ax, color='blue')

gdf2.plot(ax=ax, color='green')

plt.show()

gdf_joined.plot()