openlayers6结合geoserver实现地图空间查询(附源码下载)

Posted 2021-03-23 giserhome

前言

之前写过一篇 openlayers4 版本的地图空间查询文章，但是由于是封装一层 js 代码写的，很多初学者看起来比较有点吃力，所以本篇文章重新写一篇地图空间查询文章，直接基于最新版本 openlayers6 写的，纯粹 html + js + css形式，没有任何封装。

内容概览

1.基于 openlayers6 实现地图空间查询
2.源代码 demo 下载

效果图如下：

具体实现过程

• html 样式

html, body, #map {
height: 100%;
padding: 0;
margin: 0;
}
.ol-popup {
position: absolute;
background-color: white;
-webkit-filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));
filter: drop-shadow(0 1px 4px rgba(0,0,0,0.2));
padding: 15px;
border-radius: 10px;
border: 1px solid #cccccc;
bottom: 12px;
left: -50px;
min-width: 280px;
}
.ol-popup:after, .ol-popup:before {
top: 100%;
border: solid transparent;
content: " ";
height: 0;
width: 0;
position: absolute;
pointer-events: none;
}
.ol-popup:after {
border-top-color: white;
border-width: 10px;
left: 48px;
margin-left: -10px;
}
.ol-popup:before {
border-top-color: #cccccc;
border-width: 11px;
left: 48px;
margin-left: -11px;
}
.ol-popup-closer {
text-decoration: none;
position: absolute;
top: 2px;
right: 8px;
}
.ol-popup-closer:after {
content: "?";
}

• 矢量图层默认样式以及高亮样式

//绘制geojson矢量图层样式
var geoJsonStyle = new ol.style.Style({
stroke: new ol.style.Stroke({
color: ‘#e6d933‘,
lineDash: [4],
width: 3
}),
fill: new ol.style.Fill({
color: ‘rgba(255, 255, 0, 0.1)‘
})
});
//绘制geojson矢量图层高亮样式
var geoJsonHLightStyle = new ol.style.Style({
stroke: new ol.style.Stroke({
color: ‘#33CCFF‘,
lineDash: [4],
width: 3
}),
fill: new ol.style.Fill({
color: ‘rgba(255, 255, 0, 0.1)‘
})
});

• 创建矢量图层以及绘制工具图层

var geojsonLayer = new ol.layer.Vector({
source: new ol.source.Vector(),
style: geoJsonStyle
});
 
//绘制工具图形
var drawsource = new ol.source.Vector();
var drawlayer = new ol.layer.Vector({
source: drawsource
});
var layers = [
new ol.layer.Tile({
source: new ol.source.OSM()
}),
/*new ol.layer.Tile({
source: new ol.source.TileArcGISRest({
url: ‘https://server.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer‘
})
}),*/
drawlayer,
geojsonLayer,
];

• 创建地图

var map = new ol.Map({
layers: layers,
overlays: [overlay],
target: ‘map‘,
view: new ol.View({
projection: ‘EPSG:4326‘,
center: [104.114129, 37.550339],
zoom: 4
})
});

• 监听地图鼠标移动事件，设置选择矢量图层要素高亮以及弹出气泡窗口效果

//监听地图鼠标移动事件
map.on(‘pointermove‘,function(e) {
if (e.dragging) {
return;
}
var feature =map.forEachFeatureAtPixel(e.pixel,
function(feature) {
return feature;
});
//console.log(‘feature‘,feature);
 
if(feature==undefined || !feature.values_.map_num){//捕捉不到矢量数据，设置矢量图层默认样式
geojsonLayer.getSource().forEachFeature(function(feature) {
feature.setStyle(geoJsonStyle);
});
//隐藏气泡窗口
overlay.setPosition(undefined);
closer.blur();
}else{//捕捉到矢量数据，设置矢量图层高亮样式
if(feature.values_ && feature.values_.map_num){
feature.setStyle(geoJsonHLightStyle);
//弹出气泡窗口
var coordinate = e.coordinate;
content.innerHTML = ‘图斑编号:‘+feature.values_.map_num+‘</br>图斑描述:‘+feature.values_.description;
overlay.setPosition(coordinate);
}
}
})

• 空间查询核心函数

var geoserverUrl = ‘http://localhost:8080/geoserver/GIS‘;
/*空间查询图层
*@method queryByPolygon
*@param polygon 空间范围
*@param typeName 图层名称
*@return null
*/
function queryByPolygon(polygon, typeName, callback){
var filter =
‘<Filter xmlns="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml">‘;
filter += ‘<And>‘;
filter += ‘<Intersects>‘;
filter += ‘<PropertyName>geom</PropertyName>‘;
filter += ‘<gml:Polygon>‘;
filter += ‘<gml:outerBoundaryIs>‘;
filter += ‘<gml:LinearRing>‘;
filter += ‘<gml:coordinates>‘ + polygon + ‘</gml:coordinates>‘;
filter += ‘</gml:LinearRing>‘;
filter += ‘</gml:outerBoundaryIs>‘;
……

完整demo源码见小专栏文章尾部：GIS之家小专栏

文章尾部提供源代码下载，对本专栏感兴趣的话，可以关注一波