geojson_utils.py 文件源码

def draw_circle(radius_in_meters, center_point, steps=15):
    """
    get a circle shape polygon based on centerPoint and radius

    Keyword arguments:
    point1  -- point one geojson object
    point2  -- point two geojson object

    if(point inside multipoly) return true else false
    """
    steps = steps if steps > 15 else 15
    center = [center_point['coordinates'][1], center_point['coordinates'][0]]
    dist = (radius_in_meters / 1000) / 6371
    # convert meters to radiant
    rad_center = [number2radius(center[0]), number2radius(center[1])]
    # 15 sided circle
    poly = []
    for step in range(0, steps):
        brng = 2 * math.pi * step / steps
        lat = math.asin(math.sin(rad_center[0]) * math.cos(dist) +
                        math.cos(rad_center[0]) * math.sin(dist) * math.cos(brng))
        lng = rad_center[1] + math.atan2(math.sin(brng) * math.sin(dist)
                                         * math.cos(rad_center[0]), math.cos(dist) - math.sin(rad_center[0]) * math.sin(lat))
        poly.append([number2degree(lng), number2degree(lat)])
    return {"type": "Polygon", "coordinates": [poly]}