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Chinmay
Chinmay

Reputation: 145

Generating evenly spaced points on grid using Python?

I am trying to plot out n evenly spaced points inside a polygon which is the site shown below on a google map. Right now, I've managed to do this using gmplot.

Google Map

My aim is to create a grid of points inside the polygon.

My recent approach is using np.meshgrid and then selecting random points from the grid. Below is the code which I use to get the points. But,the result is not what I expected.

def random_points_within(poly, num_points):
    min_x, min_y, max_x, max_y = poly.bounds
    x = (np.linspace(min_x,max_x,1000))
    y=  (np.linspace(min_y,max_y,1000))
    xx,yy = np.meshgrid(x,y,sparse=True)
    xx=xx[0]
    points = []

    while len(points) < num_points:
        random_point = Point([random.choice(xx), random.choice(yy)])
        if (random_point.within(poly)):
            points.append(list(random_point.coords))
    print(min_x,max_x,max_y,min_y)
    return points
    #poly is a polygon created by the edges for the site

Update:

Tried iterating through all the points on the meshgrid and ended up getting the below image.

def random_points_within(poly, num_points):
    min_x, min_y, max_x, max_y = poly.bounds
    x = (np.linspace(min_x,max_x,num_points))
    y=  (np.linspace(min_y,max_y,num_points))
    xx,yy = np.meshgrid(x,y,sparse=True)
    xx = xx.reshape((np.prod(xx.shape),))
    yy = yy.reshape((np.prod(yy.shape),))
    points = []

    for (x,y) in zip(xx,yy):
       random_point = Point([x, y])
       if (random_point.within(poly)):
          points.append(list(random_point.coords))
    print(min_x,max_x,max_y,min_y)
    return points,xx,yy

Output:

enter image description here

Is there a way to get evenly spaced points ?

Upvotes: 0

Views: 2457

Answers (1)

Nathan
Nathan

Reputation: 3648

Since I don't have access to the poly object best I can do is make a guess:

def random_points_within(poly, num_points):
    min_x, min_y, max_x, max_y = poly.bounds
    x = (np.linspace(min_x,max_x,num_points))
    y=  (np.linspace(min_y,max_y,num_points))
    xx,yy = np.meshgrid(x,y,sparse=True)
    xx = xx.reshape((np.prod(xx.shape),))
    yy = yy.reshape((np.prod(yy.shape),))
    points = []

    for x in xx:
       for y in yy:
           random_point = Point([x, y])
           if (random_point.within(poly)):
              points.append(list(random_point.coords))
    print(min_x,max_x,max_y,min_y)
    return points,xx,yy

The only change I made compared to your program is that it loops both over xx and yy so you'll cover an area rather than a line.

Upvotes: 1

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