2

我使用坐标数组创建了一条折线，其代码改编自 https://google-developers.appspot.com/maps/documentation/javascript/examples/polyline-simple

虽然第一种（可能也是最糟糕的）制作这条线的方法只是一个巨大的纬度/经度点列表。还在学习编程技巧，我很抱歉。我是地理学家而不是程序员！

我想从那条线上获取高程并创建一个高程剖面图。我是 JS 新手，不知道如何调试不起作用的东西。我似乎无法使用折线中的坐标填充路径数组。

它当前设置为将 bikeCourseCoordinates 推送到一个新数组，然后将其用作路径。我尝试使用 bikeCourseCoordinates 数组作为“路径”，但这也不起作用。

在线（但不是工作版本）在这里： http ://geography.uoregon.edu:50000/bentesting/map_try3.html

function drawPath() {

  // Create a new chart in the elevation_chart DIV.
  chart = new google.visualization.ColumnChart(document.getElementById('elevation_chart'));

  var path = new Array;
  path.push(bikeCourseCoordinates);


  // Create a PathElevationRequest object using this array.
  var pathRequest = {
    'path': path,
    'samples': 256
  }

  // Initiate the path request.
  elevator.getElevationAlongPath(pathRequest, plotElevation);
}

// Takes an array of ElevationResult objects, draws the path on the map
// and plots the elevation profile on a Visualization API ColumnChart.
function plotElevation(results, status) {
  if (status == google.maps.ElevationStatus.OK) {
    elevations = results;

    // Extract the elevation samples from the returned results
    // and store them in an array of LatLngs.
    var elevationPath = [];
    for (var i = 0; i < results.length; i++) {
      elevationPath.push(elevations[i].location);
    }

    // Extract the data from which to populate the chart.
    // Because the samples are equidistant, the 'Sample'
    // column here does double duty as distance along the
    // X axis.
    var data = new google.visualization.DataTable();
    data.addColumn('string', 'Sample');
    data.addColumn('number', 'Elevation');
    for (var i = 0; i < results.length; i++) {
      data.addRow(['', elevations[i].elevation]);
    }

    // Draw the chart using the data within its DIV.
    document.getElementById('elevation_chart').style.display = 'block';
    chart.draw(data, {
      width: 640,
      height: 200,
      legend: 'none',
      titleY: 'Elevation (m)'
    });
  }
}
4

2 回答 2

3

您是否要重现该页面上的第三个示例？https://developers.google.com/maps/customize

如果是，我已经做到了，但没有图表效果

这是我的代码

这在你的脑海中

script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=true"
script type="text/javascript" src="https://www.google.com/jsapi"
script src="https://www.google.com/uds/?file=visualization&amp;v=1&amp;packages=columnchart" type="text/javascript"

这在正文标记之前的页脚中

var elevator;
var map;
var chart;
var infowindow = new google.maps.InfoWindow();
var polyline;
var mapCenter = new google.maps.LatLng(-21.745585792425,165.91141052497);


// Load the Visualization API and the columnchart package.
google.load("visualization", "1", {packages: ["columnchart"]});


function initialize() {
    var mapOptions = {
        center: mapCenter,
        zoom: 13,
        mapTypeId: 'terrain'
    };

    map = new google.maps.Map(document.getElementById("map"), mapOptions);

    // Create an ElevationService.
    elevator = new google.maps.ElevationService();

    // Draw the path, using the Visualization API and the Elevation service.
    drawPath();
}


function drawPath() {

    // Create a new chart in the elevation_chart DIV.
    chart = new google.visualization.ColumnChart(document.getElementById('elevation-chart'));

    var path = bikeCourseCoordinates;

    // Create a PathElevationRequest object using this array.
    // Ask for 256 samples along that path.
    var pathRequest = {
        'path': path,
        'samples': 256
    }

    // Initiate the path request.
    elevator.getElevationAlongPath(pathRequest, plotElevation);
}



function plotElevation(results, status) {
  if (status == google.maps.ElevationStatus.OK) {
    elevations = results;

    // Extract the elevation samples from the returned results
    // and store them in an array of LatLngs.
    var elevationPath = [];
    for (var i = 0; i < results.length; i++) {
      elevationPath.push(elevations[i].location);
    }

    // Display a polyline of the elevation path.
    var pathOptions = {
      path: elevationPath,
      strokeColor: '#0000CC',
      opacity: 0.9,
      map: map
    }
    polyline = new google.maps.Polyline(pathOptions);

    // Extract the data from which to populate the chart.
    // Because the samples are equidistant, the 'Sample'
    // column here does double duty as distance along the
    // X axis.
    var data = new google.visualization.DataTable();
    data.addColumn('string', 'Sample');
    data.addColumn('number', 'Elevation');
    for (var i = 0; i < results.length; i++) {
      data.addRow(['', elevations[i].elevation]);
    }

    // Draw the chart using the data within its DIV.
    document.getElementById('elevation-chart').style.display = 'block';
    chart.draw(data, {
      width: 960,
      height: 300,
      legend: 'none',
      titleY: 'Elevation (m)'
    });
  }
}



initialize();
于 2012-07-22T22:21:43.763 回答
0

我找不到问题，但这里有一些可能会有所帮助的观察结果：

I tried it just using the bikeCourseCoordinates array as the 'path'

根据 Maps API，pathRequest应该是：

var pathRequest = {
    'path': bikeCourseCoordinates,
    'samples': 256
}

此外，我认为以下初始部分，即：

var whitney = new google.maps.LatLng(36.578581, -118.291994);
...
...
var panamintsprings = new google.maps.LatLng(36.339722, -117.467778);
var badwater = new google.maps.LatLng(36.23998, -116.83171);

var bikeCourseCoordinates = [
            new google.maps.LatLng(47.67609435030702, -116.7896032333374),

<script>只有在加载地图库后才应调用直接包含在第一个内联标记中的内容。我会将它全部放入另一个函数中myInit，然后myInit从您当前名为的函数中调用initialize

上述原因是，尽管您包含了包含 maps api 的脚本标记，maps.googleapis.com/maps/api/js?sensor=false但浏览器将继续执行包含的下一个脚本块，whitney= new google.maps.Lat因为 maps.googleapis.com 是一个外部脚本，我认为这些外部脚本是异步加载的。

于 2012-06-13T05:57:50.303 回答