Get Solid-Filled Image for State Map v1

get_state_v1.py

def get_state_v1(state):
    url = make_url(state)

    IN = load_gif_url(url)

    #Drop the text at the top
    IN = IN[150:]

    #Convert 3 color channels to 1
    IN_bw = get_bw(IN)
  
    #invert colors (per docs for findContour)
    IMG = 255-IN_bw
    
    # This seems to bre required for Massachusetts
    kernel = np.ones((3,3),np.uint8)
    IMG = cv2.dilate(IMG,kernel,iterations = 1)
    
    out_img = IMG.copy()
    contours, hierarchy = cv2.findContours(out_img, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

    threshold = 0.02

    img = 255*np.ones(IN.shape, dtype=np.uint8)
    for i in xrange(len(contours)):
        cnt = contours[i]
        cnt_len = cv2.arcLength(cnt, True)
        cc = cv2.approxPolyDP(cnt, threshold * cnt_len, True)

        area = cv2.contourArea(cc)

        if cnt_len > 50 and area > 500:
            cv2.drawContours(img, contours, i, (0,0,0),thickness=cv2.cv.CV_FILLED) 

    return img