Openlayers 3坐标

Question

我是OL新人。我只需要在地图上放置一些点，理想情况下会请求将有关该点的信息写入数据库，但现在我只想提醒（坐标）点。所以，我找到了一个例子，我可以在地图上放置一些点、线和多边形。

var raster = new ol.layer.Tile({
    source: new ol.source.OSM()
  });

  var map = new ol.Map({
    layers: [raster],
    target: 'map',
    view: new ol.View({
      center: [-11000000, 4600000],
      zoom: 4
    })
  });

  var features = new ol.Collection();
  var featureOverlay = new ol.layer.Vector({
    source: new ol.source.Vector({features: features}),
    style: new ol.style.Style({
      fill: new ol.style.Fill({
        color: 'rgba(255, 255, 255, 0.2)'
      }),
      stroke: new ol.style.Stroke({
        color: '#ffcc33',
        width: 2
      }),
      image: new ol.style.Circle({
        radius: 7,
        fill: new ol.style.Fill({
          color: '#ffcc33'
        })
      })
    })
  });
  featureOverlay.setMap(map);

  var modify = new ol.interaction.Modify({
    features: features,
    // the SHIFT key must be pressed to delete vertices, so
    // that new vertices can be drawn at the same position
    // of existing vertices
    deleteCondition: function(event) {
      //var feature = event.element;
      //var coord = event.feature.getGeometry().getCoordinates();
      //coord = ol.proj.transform(coord, 'EPSG:3857', 'EPSG:4326');
      //  alert(coord);
      return ol.events.condition.shiftKeyOnly(event) &&
          ol.events.condition.singleClick(event);
    }
  });
  map.addInteraction(modify);

  var draw; // global so we can remove it later
  var typeSelect = document.getElementById('type');

  function addInteraction() {

    draw = new ol.interaction.Draw({
      features: features,
      type: /** @type {ol.geom.GeometryType} */ (typeSelect.value)
    /*draw.on('drawend', function (event) {
      // get the feature
      var feature = event.element;
      var coord = event.feature.getGeometry().getCoordinates();
      alert(coord);*/
    });


    map.addInteraction(draw);
  }


  /**
   * Handle change event.
   */
  typeSelect.onchange = function() {
    map.removeInteraction(draw);
    addInteraction();
  };

  addInteraction();
// Code of adding to DB our features

  //

<?php
/* @var $this yii\web\View */
use yii\helpers\Html;
use sibilino\yii2\openlayers\ol;
use sibilino\yii2\openlayers\OpenLayers;
?>
<!DOCTYPE html>
<html>
<head>
  <title>Draw and Modify Features</title>
  <link rel="stylesheet" href="http://openlayers.org/en/v3.18.2/css/ol.css" type="text/css">
  <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
  <script src="http://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
  <script src="http://openlayers.org/en/v3.18.2/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form class="form-inline">
  <label>Geometry type &nbsp;</label>
  <select id="type">
    <option value="Point">Point</option>
    <option value="LineString">LineString</option>
    <option value="Polygon">Polygon</option>
  </select>
</form>
<script>
</script>
</body>
</html>

它在所有库中都能正常工作，我可以在地图上放置点、线和多边形，但我无法获得我放置的点的坐标。我试图创建一些侦听器，它在这段代码中有注释，看起来像

//var feature = event.element;
  //var coord = event.feature.getGeometry().getCoordinates();
  //coord = ol.proj.transform(coord, 'EPSG:3857', 'EPSG:4326');
  //  alert(coord);

但据我所知，这种方法也会监听鼠标移动，但我遇到了一些错误，例如：

Uncaught TypeError: Cannot read property 'getGeometry' of undefined

如果有人有时间阅读这个长问题，我该怎么做，以及如何正确获取我的坐标并将其保存到数据库？

Answer 1

我只需要编辑这段代码：

function addInteraction() {

draw = new ol.interaction.Draw({
  features: features,
  type: /** @type {ol.geom.GeometryType} */ (typeSelect.value)
/*draw.on('drawend', function (event) {
  // get the feature
  var feature = event.element;
  var coord = event.feature.getGeometry().getCoordinates();
  alert(coord);*/
});


map.addInteraction(draw);

}

收件人：

function addInteraction() {

draw = new ol.interaction.Draw({
  features: features,
  type: /** @type {ol.geom.GeometryType} */ (typeSelect.value)

});

// Code of adding to DB our features

draw.on('drawend', function (event) {
  var feature = event.element;
  var coord = event.feature.getGeometry().getCoordinates();
 alert(coord);

  var title=document.getElementById('type');

   var url = "http://localhost/basic/web/index.php?r=sggis/create&title="+title.value+"&point="+coord;
   function lol(){
     var xhr = new XMLHttpRequest();
     xhr.open("GET", url, false);
     xhr.send();
   }
  lol();
});

在 yii2 控制器中，我编写了一个仅从请求中获取标题和坐标的操作。这是不安全的，但我会编辑这个。总之，我放在地图上的每个点、线或多边形都会将它们的坐标保存到 postgresSQL 的数据库中。

Openlayers 3坐标

Openlayers 3 Coords

javascript

php

yii2

openlayers-3