Google Roads API 的 Nearest Roads 函数返回的点数多于给定点，包含重复项

Question

我正在向 Google 的 Roads API 发送一些点，以将它们调整为道路。请注意，这是“最近的道路”功能，而不是“对齐道路”功能，因此这些点不会形成路径。当我得到我的结果时，返回的分数比给定的多，但其中许多分数是重复的。当我删除重复项时，比给出的要少。 该问题可以通过以下 URL 和点集重现，只需输入您自己的 API 密钥即可。我提供了 20 分，但最终得到了 35 分。

'https://roads.googleapis.com/v1/nearestRoads?points=33.9882659912109,-118.47038269043001|33.9992523193359,-118.462142944336|33.9937591552734,-118.447036743164|33.9951324462891,-118.456649780273|33.991012573242195,-118.455276489258|33.9827728271484,-118.469009399414|33.9882659912109,-118.464889526367|33.981399536132805,-118.463516235352|34.003372192382805,-118.462142944336|33.986892700195305,-118.47175598144501|33.997879028320305,-118.463516235352|34.003372192382805,-118.452529907227|33.9882659912109,-118.474502563477|33.996505737304695,-118.47175598144501|33.981399536132805,-118.466262817383|34.001998901367195,-118.463516235352|33.996505737304695,-118.46076965331999|33.9937591552734,-118.466262817383|33.9992523193359,-118.469009399414|33.9937591552734,-118.463516235352&key=INSERT_YOUR_API_KEY_HERE'

我发现 this question 有类似的问题，但它特定于 Snap To Roads，因此该解决方案不适用于此处。

Answer 1

根据the documentation，该 API 返回 1 个单向道路响应，2 个双向道路响应，并且还包括原始输入点的索引：

对于每个有效请求，Roads API 将以请求 URL 中指示的格式返回响应。 Snap to Roads 响应中可能存在以下元素。

对于每个有效请求，Roads API 将以请求 URL 中指示的格式返回响应。 Snap to Roads 响应中可能存在以下元素。

snappedPoints — 一组捕捉点。每个点由以下字段组成：

• location - 包含纬度和经度值。
• originalIndex — 一个整数，指示原始请求中的相应值。请求中的每个点最多映射到响应中的两个段：
  

如果附近没有道路，则不返回任何路段。
如果最近的道路是单向的，则返回一个路段。
如果最近的道路是双向的，则返回两个路段。 地点标识

因此，如果附近的道路是双向的，那么响应中的点数将是请求中的两倍。

从您的数据看来，许多道路是两条路，返回两个点，但数据是这样的，这两个点是相同的。根据您的请求返回的响应，返回了 35 个点，所有原始点都在响应中表示。

proof of concept fiddle putting the response data into a MarkerClusterer

代码sn-p：

var geocoder;
var map;

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  var bounds = new google.maps.LatLngBounds();
  var gmarkers = [];
  console.log("snappedPoints.length=" + roadsApiSnapToRoadResult.snappedPoints.length);
  for (var i = 0; i < roadsApiSnapToRoadResult.snappedPoints.length; i++) {
    var marker = new google.maps.Marker({
      position: {
        lat: roadsApiSnapToRoadResult.snappedPoints[i].location.latitude,
        lng: roadsApiSnapToRoadResult.snappedPoints[i].location.longitude,
      },
      icon: {
        url: "https://maps.gstatic.com/intl/en_us/mapfiles/markers2/measle.png",
        size: new google.maps.Size(7, 7),
        anchor: new google.maps.Point(3.5, 3.5)
      },
      title: "" + roadsApiSnapToRoadResult.snappedPoints[i].originalIndex,
      map: map
    });
    gmarkers.push(marker);
    bounds.extend(marker.getPosition());
  }
  map.fitBounds(bounds);
  var markerClusterer = new MarkerClusterer(map, gmarkers, {
    imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m',
    maxZoom: 18
  });
}
google.maps.event.addDomListener(window, "load", initialize);
var roadsApiSnapToRoadResult = {
  "snappedPoints": [{
      "location": {
        "latitude": 33.988152465043711,
        "longitude": -118.4704415352344
      },
      "originalIndex": 0,
      "placeId": "ChIJ07TI4bi6woARVzS3zNDS75A"
    },
    {
      "location": {
        "latitude": 33.999373102445233,
        "longitude": -118.46239768997125
      },
      "originalIndex": 1,
      "placeId": "ChIJVwy5xOm6woARsndu3i5UqVw"
    },
    {
      "location": {
        "latitude": 33.999373102445233,
        "longitude": -118.46239768997125
      },
      "originalIndex": 1,
      "placeId": "ChIJVwy5xOm6woARs3du3i5UqVw"
    },
    {
      "location": {
        "latitude": 33.993767373940663,
        "longitude": -118.44703991835411
      },
      "originalIndex": 2,
      "placeId": "ChIJHUeXXoy6woARSrO6Q7pKMCc"
    },
    {
      "location": {
        "latitude": 33.993767373940663,
        "longitude": -118.44703991835411
      },
      "originalIndex": 2,
      "placeId": "ChIJHUeXXoy6woARS7O6Q7pKMCc"
    },
    {
      "location": {
        "latitude": 33.995020152633714,
        "longitude": -118.45642063549312
      },
      "originalIndex": 3,
      "placeId": "ChIJbdaMr-y6woAR7kSZm8ROfMc"
    },
    {
      "location": {
        "latitude": 33.995020152633714,
        "longitude": -118.45642063549312
      },
      "originalIndex": 3,
      "placeId": "ChIJbdaMr-y6woAR70SZm8ROfMc"
    },
    {
      "location": {
        "latitude": 33.991049979984176,
        "longitude": -118.45535641955625
      },
      "originalIndex": 4,
      "placeId": "ChIJtb81pZO6woARcCdVIfSh_G8"
    },
    {
      "location": {
        "latitude": 33.991049979984176,
        "longitude": -118.45535641955625
      },
      "originalIndex": 4,
      "placeId": "ChIJtb81pZO6woARcSdVIfSh_G8"
    },
    {
      "location": {
        "latitude": 33.98285945845808,
        "longitude": -118.46908608980472
      },
      "originalIndex": 5,
      "placeId": "ChIJISAPfbu6woARyKxdnrZG5oE"
    },
    {
      "location": {
        "latitude": 33.98285945845808,
        "longitude": -118.46908608980472
      },
      "originalIndex": 5,
      "placeId": "ChIJISAPfbu6woARyaxdnrZG5oE"
    },
    {
      "location": {
        "latitude": 33.988333802620495,
        "longitude": -118.46480571557542
      },
      "originalIndex": 6,
      "placeId": "ChIJs7rlQb66woARIeOfKMcdQX4"
    },
    {
      "location": {
        "latitude": 33.981527850209972,
        "longitude": -118.4636347455167
      },
      "originalIndex": 7,
      "placeId": "ChIJnZB4paK6woARXLQoGfodVh0"
    },
    {
      "location": {
        "latitude": 33.981527850209972,
        "longitude": -118.4636347455167
      },
      "originalIndex": 7,
      "placeId": "ChIJnZB4paK6woARXbQoGfodVh0"
    },
    {
      "location": {
        "latitude": 34.003497235152565,
        "longitude": -118.46240183188755
      },
      "originalIndex": 8,
      "placeId": "ChIJd5Hp-ue6woARatY78BByNBg"
    },
    {
      "location": {
        "latitude": 34.003497235152565,
        "longitude": -118.46240183188755
      },
      "originalIndex": 8,
      "placeId": "ChIJd5Hp-ue6woARa9Y78BByNBg"
    },
    {
      "location": {
        "latitude": 33.98685767022473,
        "longitude": -118.47172496327262
      },
      "originalIndex": 9,
      "placeId": "ChIJ3TKdobm6woARS2DIe-NRymk"
    },
    {
      "location": {
        "latitude": 33.997747613047771,
        "longitude": -118.46341368261827
      },
      "originalIndex": 10,
      "placeId": "ChIJc3IO_um6woARWgni7EMZaJ0"
    },
    {
      "location": {
        "latitude": 33.997747613047771,
        "longitude": -118.46341368261827
      },
      "originalIndex": 10,
      "placeId": "ChIJc3IO_um6woARWwni7EMZaJ0"
    },
    {
      "location": {
        "latitude": 34.00333556691659,
        "longitude": -118.45250243554641
      },
      "originalIndex": 11,
      "placeId": "ChIJK7ABtu-6woARyCzwvT7-vco"
    },
    {
      "location": {
        "latitude": 34.00333556691659,
        "longitude": -118.45250243554641
      },
      "originalIndex": 11,
      "placeId": "ChIJK7ABtu-6woARySzwvT7-vco"
    },
    {
      "location": {
        "latitude": 33.988346309645785,
        "longitude": -118.4743705301974
      },
      "originalIndex": 12,
      "placeId": "ChIJ1TslIri6woARQ_h9FkDa-yc"
    },
    {
      "location": {
        "latitude": 33.9964313646278,
        "longitude": -118.47170049959587
      },
      "originalIndex": 13,
      "placeId": "ChIJhZYhN8S6woAR5pUEEEhYbCU"
    },
    {
      "location": {
        "latitude": 33.9964313646278,
        "longitude": -118.47170049959587
      },
      "originalIndex": 13,
      "placeId": "ChIJhZYhN8S6woAR55UEEEhYbCU"
    },
    {
      "location": {
        "latitude": 33.981307554994437,
        "longitude": -118.46641918691026
      },
      "originalIndex": 14,
      "placeId": "ChIJxTT5KKO6woAR_uY0J0oCLDU"
    },
    {
      "location": {
        "latitude": 33.981307554994437,
        "longitude": -118.46641918691026
      },
      "originalIndex": 14,
      "placeId": "ChIJxTT5KKO6woAR_-Y0J0oCLDU"
    },
    {
      "location": {
        "latitude": 34.002195599071726,
        "longitude": -118.46391163712804
      },
      "originalIndex": 15,
      "placeId": "ChIJqXQkrcK6woAR_sD5qVq2Yl8"
    },
    {
      "location": {
        "latitude": 34.002195599071726,
        "longitude": -118.46391163712804
      },
      "originalIndex": 15,
      "placeId": "ChIJqXQkrcK6woAR_8D5qVq2Yl8"
    },
    {
      "location": {
        "latitude": 33.99648760375095,
        "longitude": -118.46073154820924
      },
      "originalIndex": 16,
      "placeId": "ChIJl0OqT-q6woARstLIStpm2NU"
    },
    {
      "location": {
        "latitude": 33.99648760375095,
        "longitude": -118.46073154820924
      },
      "originalIndex": 16,
      "placeId": "ChIJl0OqT-q6woARs9LIStpm2NU"
    },
    {
      "location": {
        "latitude": 33.993670902273607,
        "longitude": -118.46619470748932
      },
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      "placeId": "ChIJWes6V8C6woARc4NO9L0r978"
    },
    {
      "location": {
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        "longitude": -118.46882770430223
      },
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      "placeId": "ChIJ2TxBfcO6woAR4oW0l5gn22c"
    },
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        "longitude": -118.46882770430223
      },
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    },
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        "longitude": -118.46333135141523
      },
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      "placeId": "ChIJL1Q9H8C6woAR6JtmbvA0dcU"
    },
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        "latitude": 33.99367154305785,
        "longitude": -118.46333135141523
      },
      "originalIndex": 19,
      "placeId": "ChIJL1Q9H8C6woAR6ZtmbvA0dcU"
    }
  ]
}

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://cdn.rawgit.com/googlemaps/v3-utility-library/master/markerclustererplus/src/markerclusterer.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?ext=.js"></script>
<div id="map_canvas"></div>