How to display Polygon List into one Graph with For Loops

Question

so I'm working on a Line of Sight script where the Polygons act as buildings and return a boolean value based on whether a line intersects with a Polygon.

The logic behind it works, but when I try to integrate more Polygons from a list called polycoords and use a For Loop so it can instantiate it on the Graph, it comes out as two separate graphs rather than a single one.

import numpy as np
import matplotlib.pyplot as plt
import shapely.geometry
from shapely.geometry import LineString
from shapely.geometry import Point, Polygon
import descartes

origin = [-1.0, 0.0] # Set a point to view from
quality = 7 # Number of grid points squared
polycoords = [[[-1, 1], [-1, 0.5], [0, 0.5], [0, 1]],[[1, -1], [1, -0.5], [0, -0.5], [-0, -1]]] # Coordinates of the Polygon
fullresults = []
newbool = []

def los (origin, quality, polycoords):
    
    for buildingpoints in range(len(polycoords)):
        x = np.linspace(-1,1,quality)
        y = np.linspace(-1,1,quality)
        X,Y = np.meshgrid(x,y)
        clip_poly = shapely.geometry.Polygon(polycoords[buildingpoints]) 
        fig = plt.figure()
        ax = fig.add_subplot(111)
        polygonbuilding = ax.add_patch(descartes.PolygonPatch(clip_poly, fc='pink', alpha=0.3))
        positions = np.vstack([Y.ravel(), X.ravel()])

        for i in range(len(positions)):
            for j in range(len(positions[i])):
                plt.scatter(*positions[::-1])
                x1 = positions[0][j]
                y1 = positions[1][j]
                line = LineString([origin, (x1, y1)])

                if line.intersects(clip_poly) == True:
                    ax.plot(*np.array(line).T, color='red', linewidth=1, solid_capstyle='round')
                else:
                    ax.plot(*np.array(line).T, color='green', linewidth=1, solid_capstyle='round')

                boolintersect = line.intersects(clip_poly)
                listresults = origin, [x1,y1],boolintersect
                fullresults.append(listresults)
                boollist = [x[2] for x in fullresults]
                newbool.append(sum(boollist))
                
    return(fullresults, newbool)

def analysis (losresults):
        percenteq = round((100-(newbool[-1]/len(fullresults))*100))
        print (percenteq,'% of the space is PUBLICALLY visible from point', fullresults[0][0])
        print (100-percenteq,'% of the space is PRIVATE/ISNT visible from point', fullresults[0][0])
        
los(origin, quality, polycoords)
analysis (los)
plt.show()

The results show two separate graphs when I need just one with both polygons present. I believe it's something to do with the structure of my code regarding the For loops, but I'm still pretty new and not too sure how to solve this.

score 0 · Accepted Answer · answered Oct 08 '20 at 01:34

Resolved meshgrid creation in the loop has been moved out and done once as given below:

import numpy as np
import matplotlib.pyplot as plt
import shapely.geometry
from shapely.geometry import LineString
from shapely.geometry import Point, Polygon
import descartes

origin = [-1.0, 0.0] # Set a point to view from
quality = 7 # Number of grid points squared
polycoords = [[[-1, 1], [-1, 0.5], [0, 0.5], [0, 1]],[[1, -1], [1, -0.5], [0, -0.5], [-0, -1]]] # Coordinates of the Polygon
fullresults = []
newbool = []

def init (origin, quality):
    global ax, positions
    x = np.linspace(-1,1,quality)
    y = np.linspace(-1,1,quality)
    X,Y = np.meshgrid(x,y)
    fig = plt.figure()
    ax = fig.add_subplot(111)
    positions = np.vstack([Y.ravel(), X.ravel()])
        
def los (origin, quality, polycoords):
    global ax, positions
    for buildingpoints in range(len(polycoords)):
        clip_poly = shapely.geometry.Polygon(polycoords[buildingpoints]) 
        polygonbuilding = ax.add_patch(descartes.PolygonPatch(clip_poly, fc='pink', alpha=0.3))

        for i in range(len(positions)):
            for j in range(len(positions[i])):
                plt.scatter(*positions[::-1])
                x1 = positions[0][j]
                y1 = positions[1][j]
                line = LineString([origin, (x1, y1)])

                if line.intersects(clip_poly) == True:
                    ax.plot(*np.array(line).T, color='red', linewidth=1, solid_capstyle='round')
                else:
                    ax.plot(*np.array(line).T, color='green', linewidth=1, solid_capstyle='round')

                boolintersect = line.intersects(clip_poly)
                listresults = origin, [x1,y1],boolintersect
                fullresults.append(listresults)
                boollist = [x[2] for x in fullresults]
                newbool.append(sum(boollist))
                
    return(fullresults, newbool)

def analysis (losresults):
        percenteq = round((100-(newbool[-1]/len(fullresults))*100))
        print (percenteq,'% of the space is PUBLICALLY visible from point', fullresults[0][0])
        print (100-percenteq,'% of the space is PRIVATE/ISNT visible from point', fullresults[0][0])
        
init (origin, quality)
los(origin, quality, polycoords)
analysis (los)
plt.show()

How to display Polygon List into one Graph with For Loops

1 Answers1