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之前，我问了一个问题“如何从 OpenStreetMap 数据中找到街道交叉口的列表？ ”。<way>我修复了上一篇文章中的代码，该代码根据对上一个问题的响应来查找两个或多个 s 共享的节点。它（几乎）现在可以工作，我可以收集街道交叉口的坐标。（仅使用<way>具有标签属性 'primary'、'secondary'、'residential' 或 'tertiary' 的 s 来查找多个 s 共享的节点<way>解决了问题。我过滤掉了其他<way>s，例如带有标签属性“建筑”）

我现在面临的问题是我收集的交叉点坐标并不详尽，我不知道这是由于OpenStreetMap数据的限制还是我的代码仍然混乱。请看下图。

地图上的大头针指示交叉点的纬度/经度坐标。 错过了一些十字路口。

谷歌地图上的大头针表示从 OpenStreeMap 收集的交叉点的纬度/经度坐标。尽管放置的引脚正确定位在交叉点上，但我使用的技术未能找到一些交叉点，例如同一图中红色箭头所指的交叉点。

我用来获取这些坐标的 osm 文件（xml 文件）是：https ://dl.dropboxusercontent.com/u/1047998/WashingtonDC.osm （此文件位于我的保管箱的公用文件夹中。如果它不可用，请见谅。 )

我用来抓取数据的代码如下：

def get_intersections(self, osm, input_type='file'):
    """
    This method reads the passed osm file (xml) and finds intersections (nodes that are shared by two or more roads)

    :param osm: An osm file or a string from get_osm()
    """
    intersection_coordinates = []
    if input_type == 'file':
        tree = ET.parse(osm)
        root = tree.getroot()
        children = root.getchildren()
    elif input_type == 'str':
        tree = ET.fromstring(osm)
        children = tree.getchildren()

    counter = {}
    for child in children:
        if child.tag == 'way':
            # Check if the way represents a "highway (road)"
            # If the way that we are focusing right now is not a road,
            # continue without checking any nodes
            road = False
            road_types = ('primary', 'secondary', 'residential', 'tertiary', 'service') 
            for item in child:
                if item.tag == 'tag' and item.attrib['k'] == 'highway' and item.attrib['v'] in road_types: 
                    road = True

            if not road:
                continue

            for item in child:
                if item.tag == 'nd':
                    nd_ref = item.attrib['ref']
                    if not nd_ref in counter:
                        counter[nd_ref] = 0
                    counter[nd_ref] += 1

    # Find nodes that are shared with more than one way, which
    # might correspond to intersections
    intersections = filter(lambda x: counter[x] > 1,  counter)


    # Extract intersection coordinates
    # You can plot the result using this url.
    # http://www.darrinward.com/lat-long/
    for child in children:
        if child.tag == 'node' and child.attrib['id'] in intersections:
            coordinate = child.attrib['lat'] + ',' + child.attrib['lon']
            intersection_coordinates.append(coordinate)
    return intersection_coordinates

我感谢任何意见、建议和解决方案。如果您能建议我收集交叉点坐标的任何其他方法，那也很棒。

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