Try to count building

I tried to count building from a gmaps image using opencv. Here's the code I used from an answer in stackoverflow :

import cv2
import numpy as np

image = cv2.imread('converted2.jpg')

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blur = cv2.medianBlur(gray, 5)
sharpen_kernel = np.array([[-1,-1,-1], [-1,9,-1], [-1,-1,-1]])
sharpen = cv2.filter2D(blur, -1, sharpen_kernel)

thresh = cv2.threshold(sharpen,160,255, cv2.THRESH_BINARY_INV)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=2)

cnts = cv2.findContours(close, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]

min_area = 10
max_area = 1000000
image_number = 0
for c in cnts:
    area = cv2.contourArea(c)
    if area > min_area and area < max_area:
        x,y,w,h = cv2.boundingRect(c)
        ROI = image[y:y+h, x:x+w]
        cv2.imwrite('ROI_{}.png'.format(image_number), ROI)
        cv2.rectangle(image, (x, y), (x + w, y + h), (50,255,10), 2)
        image_number += 1

cv2.imshow('sharpen', sharpen)
cv2.imshow('close', close)
cv2.imshow('thresh', thresh)
print(image_number)
cv2.imshow('image', image)
cv2.waitKey()

The image is black and white. I tried to detect how many building. But it gave me wrong number of building.

The output was 17.

The original image = The result =

Edited : I tried using different code :

org=cv2.imread('maps_converted2.jpg')
cv2.imshow('sample',org)
img = cv2.imread('maps_converted2.jpg',0)
ret,thresh = cv2.threshold(img,127,255,0)
contours,hierarchy = cv2.findContours(thresh, 1, 2)
for cnt in contours:
    x,y,w,h = cv2.boundingRect(cnt)
    img = cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,0),2)
cv2.imshow("image", img)
cv2.waitKey()

This is the result :