CODEWITHSUNDEEP
pythonpython-3.x
Caerus
Caerus

Reputation: 674

Divide a Rectangle into N Equal Subrectangles

I have a rectangular grid that is defined by longitude and latitude pairs. I would like to divide this rectangle into N equal subrectangles. For example, suppose we have a rectangle defined by the following four points:

1: (0,0)
2: (0,2)
3: (2,2)
4: (2,0)

Suppose we wish to divide this rectangle into 4 equal subrectangles so that we have the following:

First subrectangle:
1. [(0,0),(0,1),(1,1),(1,1)]
Second subrectangle:
2. [(0,1),(0,2),(1,2),(1,1)]
Third subrectangle:
3. [(1,1),(1,2),(2,2),(2,1)]
Fourth subrectangle:
4. [(1,0),(1,1),(2,1),(2,0)]

The order of the subrectangles is irrelevant.

My approach is to construct latitude and longitude lists and use a double loop to call the items from each list.

def sub_rectangles(factor,westlimit=0, southlimit=0, eastlimit=2, northlimit=2):
    table=list()
    #Divide the difference between the limits by the factor
    lat_adj_factor=(northlimit-southlimit)/factor
    lon_adj_factor=(eastlimit-westlimit)/factor
    #Create longitude and latitude lists
    lat_list=[]
    lon_list=[]
    for i in range(factor+1):
        lon_list.append(westlimit)
        westlimit+=lon_adj_factor
    for i in range(factor+1):
        lat_list.append(southlimit)
        southlimit+=lat_adj_factor
    #Build a list of longitude and latitude pairs
    for i in range(0,len(lon_list)-1):
        for j in range(0,len(lat_list)-1):
            table.append([lon_list[i],lat_list[j],lon_list[i+1],lat_list[j],lon_list[i+1],[lat_list[j+1]]]) 
    return table

Unfortunately the output is mostly nonsense. Any suggestions?

Upvotes: 1

Views: 1031

Answers (1)

Caerus
Caerus

Reputation: 674

I think the error is in the coordinate pair construction. I believe the following works; do you agree?

I changed this line:

table.append([lon_list[i],lat_list[j],lon_list[i+1],lat_list[j],lon_list[i+1],[lat_list[j+1]]])

To the following:

table.append([(lon_list[i],lat_list[j]),(lon_list[i+1],lat_list[j]),(lon_list[i],lat_list[j+1]),(lon_list[i+1],lat_list[j+1])])

Which gives this result: [[(0, 0), (1.0, 0), (0, 1.0), (1.0, 1.0)], [(0, 1.0), (1.0, 1.0), (0, 2.0), (1.0, 2.0)], [(1.0, 0), (2.0, 0), (1.0, 1.0), (2.0, 1.0)], [(1.0, 1.0), (2.0, 1.0), (1.0, 2.0), (2.0, 2.0)]]

Upvotes: 1

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