基于OpenLayers使用WFS实现GeoServer地图要素的增删改查

1. 概述

Web Feature Service（WFS）接口标准定义了一组接口，用于在Internet上访问要素和要素属性级别的地理信息。WFS提供了检索或查询矢量要素的方法，这种方法独立于它们发布的底层数据存储，WFS还可以更新或删除矢量要素。WFS的实例还能够存储查询，以便使客户机应用程序能够在稍后的时间点检索或执行查询

更多信息可参考：

中文版站点（翻译不完全准确）：WFS-简介 — OGC e-Learning 2.0.0 文档 (osgeo.cn)

WFS服务器必须支持的操作：

  • GetCapabilities：返回一个文档，该文档描述由服务器提供的WFS服务提供的功能和资源

  • DescribeFeatureType：返回WFS实例提供或接受的功能类型和功能属性的结构描述

  • ListStoredQueries：返回存储在WFS实例中的查询列表

  • DescribeStoredQueries：返回存储在WFS实例中的查询的说明

  • GetFeature：从通过WFS发布的数据存储中返回要素实例的选择

WFS服务器通常也支持的操作：

  • GetPropertyValue：检索一组要素实例的要素特性值或复杂要素特性值的一部分
  • GetFeatureWithLock：提供与GetFeature请求类似的功能，但具有锁定特性的附加功能，可能是为了后续更新或更改
  • LockFeature：锁定一组要素实例，以便在锁定到位时，其他操作都不能修改数据
  • Transaction：允许插入、更新或删除要素实例及其属性
  • CreateStoredQuery：创建并存储一个查询，客户机可以在稍后的时间点快速地触发该查询
  • DropStoredQuery：从服务器中删除以前存储的查询

参考：WFS参考 — GeoServer 2.19.x User Manual (osgeo.cn)

GeoServer作为GIS服务器，支持WFS定义的一系列操作

WFS操作大部分支持KVP格式（URL里包含键值对的形式）和XML格式，少部分只支持XML格式（主要是更新与新增操作）

编写XML终究繁琐，OpenLayers支持OGC的WFS规范，可以基于WFS来对空间数据进行增、删、改、查（CRUD）

本文基于OpenLayers提供的WFS操作API，实现对GeoServer发布的空间数据进行增、删、改、查

本文大量参考了这篇文章：OpenLayers教程：网络要素服务（WFS） - 知乎 (zhihu.com)

2. 环境准备

GeoServer的下载与配置跨域可参考：

从官方下载的GeoServer带有示例数据，参考：

登录GeoServer，默认登录账户密码是：

  • 用户名: admin
  • 密码: geoserver

笔者这里使用的数据是 Tasmania roads：

image-20220724222005331

另外，需要将此数据开启读写权限：

image-20220724222338174

使用的OpenLayers版本是最新版6.15.1，CDN引入：

<link rel="stylesheet"
      href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/css/ol.css" type="text/css">
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/build/ol.js"></script>

3. 查询要素

这里的查询要素主要是指使用GetFeature操作，即获取要素

GetFeature操作可以使用KVP格式构造URL地址,参考官方自带示例:

image-20220724223753454

可以通过构造URL来实现多种查询，构造的具体参数可以参考：

笔者这里查询Tasmania roads的所有要素并返回JSON格式：

http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json

此外我们还可以使用GeoServer自带的图层预览来复制构造的URL：

image-20220724224449695

直接在new ol.source.Vector中写入url参数，就可以利用WFS的KVP进行要素的查询，核心代码如下：

const vectorLayer = new ol.layer.Vector({
    source: new ol.source.Vector({
        url: 'http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json',
        format: new ol.format.GeoJSON()
    })
});
map.addLayer(vectorLayer);

完整代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <link rel="stylesheet"
        href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/css/ol.css" type="text/css">
    <script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/build/ol.js"></script>
    <style>
        html,
        body {
            height: 100%;
        }

        body {
            margin: 0;
            padding: 0;
        }

        #map {
            height: 100%;
        }
    </style>
</head>

<body>
    <div id="map"></div>
    <script>
        const map = new ol.Map({
            target: 'map',
            layers: [],
            view: new ol.View({
                center: [147.01, -42.26],
                zoom: 8,
                projection: 'EPSG:4326'
            })
        });
        map.addLayer(new ol.layer.WebGLTile({
            source: new ol.source.OSM()
        }));
        const vectorLayer = new ol.layer.Vector({
            source: new ol.source.Vector({
                url: 'http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json',
                format: new ol.format.GeoJSON()
            }),
            style: new ol.style.Style({
                stroke: new ol.style.Stroke({
                    color: '#0000ff',
                    width: 2
                })
            })
        });
        map.addLayer(vectorLayer);
    </script>

</body>

</html>

加载的地图如下：

image-20220724230249890

4. 添加要素

更新、添加、删除要素操作都不支持KVP格式，所以只能使用XML文档的形式来请求

一个完整的XML字段解释如下图：

image-20220725004346519

参考GeoServer自带的添加要素的示例：

image-20220724230653974

编写XML字符过于繁琐，OpenLayers提供了编写WFS XML的API：

image-20220724230933323

参考OpenLayers的API文档：OpenLayers v6.15.1 API - Class: WFS

核心代码如下：

// 服务配置，命名空间、图层、服务地址等
const geoserverData = {
    workSpaceName: 'topp',
    uri: 'http://www.openplans.org/topp',
    wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
    layer: 'tasmania_roads'
}

function addFeatureWFS(features) {
    let WFS = new ol.format.WFS();
    // 生成XML格式的WFS请求信息
    let transact_xml = WFS.writeTransaction(
        features, null, null,
        {
            srcName: 'EPSG:4326',
            featureNS: geoserverData.uri,
            featurePrefix: geoserverData.workSpaceName,
            featureType: [geoserverData.layer],
        }
    );
    // 将XML格式请求信息序列化为字符串格式
    transact_str = (new XMLSerializer()).serializeToString(transact_xml);
    // 使用Fetch将请求发送到后端
    fetch('http://localhost:8080/geoserver/wfs', {
        method: 'POST',
        body: transact_str,
        headers: {
            'Content-Type': 'text/xml'
        }
    }).then(res => res.text()).then(res => {
        console.log(res);
    });
}

完整代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <link rel="stylesheet"
        href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/css/ol.css" type="text/css">
    <script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/build/ol.js"></script>
    <style>
        html,
        body {
            height: 100%;
        }

        body {
            margin: 0;
            padding: 0;
        }

        #map {
            height: 100%;
        }
    </style>
</head>

<body>
    <button id="draw">绘制</button>
    <button id="add">添加</button>
    <button id="exit">退出</button>
    <div id="map"></div>
    <script>
        const map = new ol.Map({
            target: 'map',
            layers: [],
            view: new ol.View({
                center: [147.01, -42.26],
                zoom: 8,
                projection: 'EPSG:4326'
            })
        });
        map.addLayer(new ol.layer.WebGLTile({
            source: new ol.source.OSM()
        }));
        const vectorLayer = new ol.layer.Vector({
            source: new ol.source.Vector({
                url: 'http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json',
                format: new ol.format.GeoJSON()
            }),
            style: new ol.style.Style({
                stroke: new ol.style.Stroke({
                    color: '#0000ff',
                    width: 2
                })
            })
        });
        map.addLayer(vectorLayer);

        // 绘制控件
        let drawedFeatures = [];
        let draw = new ol.interaction.Draw({
            source: vectorLayer.getSource(),
            type: 'MultiLineString',
            geometryName: 'the_geom'                // 注意：这里图形信息字段一定要和后端服务器一致
        });
        draw.on('drawend', (event) => {
            let feature = event.feature;
            // 为要素添加属性，我这里随便设置属性
            feature.set('TYPE', 'highway');
            drawedFeatures.push(event.feature);
        });
        map.addInteraction(draw);
        draw.setActive(false);

        document.querySelector('#add').addEventListener('click', (event) => {
            // 将绘制的要素添加到后台
            addFeatureWFS(drawedFeatures);
        });
        document.querySelector('#draw').addEventListener('click', (event) => {
            // 绘制要添加的要素
            draw.setActive(true);
        });
        document.querySelector('#exit').addEventListener('click', (event) => {
            // 退出绘制
            draw.setActive(false);
        });

        // 服务配置，命名空间、图层、服务地址等
        const geoserverData = {
            workSpaceName: 'topp',
            uri: 'http://www.openplans.org/topp',
            wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
            layer: 'tasmania_roads'
        }

        function addFeatureWFS(features) {
            let WFS = new ol.format.WFS();
            // 生成XML格式的WFS请求信息
            let transact_xml = WFS.writeTransaction(
                features, null, null,
                {
                    srcName: 'EPSG:4326',
                    featureNS: geoserverData.uri,
                    featurePrefix: geoserverData.workSpaceName,
                    featureType: [geoserverData.layer],
                }
            );
            // 将XML格式请求信息序列化为字符串格式
            transact_str = (new XMLSerializer()).serializeToString(transact_xml);
            // 使用Fetch将请求发送到后端
            fetch('http://localhost:8080/geoserver/wfs', {
                method: 'POST',
                body: transact_str,
                headers: {
                    'Content-Type': 'text/xml'
                }
            }).then(res => res.text()).then(res => {
                let transactRes = WFS.readTransactionResponse(res);
                let str = transactRes.transactionSummary.totalInserted +
                    " totalInserted!, insertIds: " + transactRes.insertIds + "\n";
                str += transactRes.transactionSummary.totalUpdated + " totalUpdated!\n";
                str += transactRes.transactionSummary.totalDeleted + " totalDeleted!";
                alert(str);
            });
        }
    </script>

</body>

</html>

注意：

  • geometryName要和后端GIS服务器的数据保持一致，它将会被写为XML标签，可以从GetFeature结果查询，参考下图
  • WFS.writeTransaction中的featureType参数是图层名字，它将会被写为XML标签，参考下图

image-20220724233355327

image-20220724233359476

增加要素后的结果：

image-20220724233608770

5. 更新要素

使用OpenLayers，更新要素的流程：

  • 加载初始要素
  • 创建选择控件选择要素
  • 创建修改控件修改要素
  • 将修改后的要素和信息写为XML
  • 序列化XML
  • 提交XML到服务器

核心代码如下：

// 服务配置，命名空间、图层、服务地址等
const geoserverData = {
    workSpaceName: 'topp',
    uri: 'http://www.openplans.org/topp',
    wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
    layer: 'tasmania_roads'
}

// 选择要素控件
let select = new ol.interaction.Select({
    layers: [vectorLayer],
    hitTolerance: 10
});
map.addInteraction(select);

// 修改要素控件
let modify = new ol.interaction.Modify({
    features: select.getFeatures()
});
// 保存修改完成的要素
let modifiedFeatures = null;    // 用于保存被修改的要素
modify.on('modifyend', (event) => {
    modifiedFeatures = event.features;
});
map.addInteraction(modify);

document.querySelector('#modify').addEventListener('click', (event) => {
    let features = [];
    modifiedFeatures.forEach(function (item, index, array) {
        features.push(item);
    });
    updateWFS(features);
});

function updateWFS(features) {
    let WFS = new ol.format.WFS();
    // 生成XML格式的WFS请求信息
    let transact_xml = WFS.writeTransaction(
        null, features, null,
        {
            srcName: 'EPSG:4326',
            featureNS: geoserverData.uri,
            featurePrefix: geoserverData.workSpaceName,
            featureType: [geoserverData.layer],
        }
    )
    // 将XML格式请求信息序列化为字符串格式
    transact_str = (new XMLSerializer()).serializeToString(transact_xml);
    // 使用Fetch将请求发送到后端
    fetch('http://localhost:8080/geoserver/wfs', {
        method: 'POST',
        body: transact_str,
        headers: {
            'Content-Type': 'text/xml'
        }
    }).then(res => res.text()).then(res => {
        console.log(res);
    });
}

完整代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <link rel="stylesheet"
        href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/css/ol.css" type="text/css">
    <script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/build/ol.js"></script>
    <style>
        html,
        body {
            height: 100%;
        }

        body {
            margin: 0;
            padding: 0;
        }

        #map {
            height: 100%;
        }
    </style>
</head>

<body>
    <button id="select">选择</button>
    <button id="modify">提交</button>
    <button id="exit">退出</button>
    <div id="map"></div>
    <script>
        const map = new ol.Map({
            target: 'map',
            layers: [],
            view: new ol.View({
                center: [147.01, -42.26],
                zoom: 8,
                projection: 'EPSG:4326'
            })
        });
        map.addLayer(new ol.layer.WebGLTile({
            source: new ol.source.OSM()
        }));
        const vectorLayer = new ol.layer.Vector({
            source: new ol.source.Vector({
                url: 'http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json',
                format: new ol.format.GeoJSON({
                    geometryName: 'the_geom'
                })
            }),
            style: new ol.style.Style({
                stroke: new ol.style.Stroke({
                    color: '#0000ff',
                    width: 2
                })
            })
        });
        map.addLayer(vectorLayer);

        document.querySelector('#select').addEventListener('click', (event) => {
            select.setActive(true);
        });
        document.querySelector('#exit').addEventListener('click', (event) => {
            select.setActive(false);
        });

        // 服务配置，命名空间、图层、服务地址等
        const geoserverData = {
            workSpaceName: 'topp',
            uri: 'http://www.openplans.org/topp',
            wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
            layer: 'tasmania_roads'
        }

        // 选择要素控件
        let select = new ol.interaction.Select({
            layers: [vectorLayer],
            hitTolerance: 10
        });
        map.addInteraction(select);
        select.setActive(false);

        // 修改要素控件
        let modify = new ol.interaction.Modify({
            features: select.getFeatures()
        });
        // 保存修改完成的要素
        let modifiedFeatures = null;    // 用于保存被修改的要素
        modify.on('modifyend', (event) => {
            modifiedFeatures = event.features;
        });
        map.addInteraction(modify);

        document.querySelector('#modify').addEventListener('click', (event) => {
            let features = [];
            modifiedFeatures.forEach(function (item, index, array) {
                features.push(item);
            });
            updateWFS(features);
        });

        function updateWFS(features) {
            let WFS = new ol.format.WFS();
            // 生成XML格式的WFS请求信息
            let transact_xml = WFS.writeTransaction(
                null, features, null,
                {
                    srcName: 'EPSG:4326',
                    featureNS: geoserverData.uri,
                    featurePrefix: geoserverData.workSpaceName,
                    featureType: [geoserverData.layer],
                }
            )
            // 将XML格式请求信息序列化为字符串格式
            transact_str = (new XMLSerializer()).serializeToString(transact_xml);
            // 使用Fetch将请求发送到后端
            fetch('http://localhost:8080/geoserver/wfs', {
                method: 'POST',
                body: transact_str,
                headers: {
                    'Content-Type': 'text/xml'
                }
            }).then(res => res.text()).then(res => {
                let transactRes = WFS.readTransactionResponse(res);
                let str = transactRes.transactionSummary.totalInserted +
                    " totalInserted!, insertIds: " + transactRes.insertIds + "\n";
                str += transactRes.transactionSummary.totalUpdated + " totalUpdated!\n";
                str += transactRes.transactionSummary.totalDeleted + " totalDeleted!";
                alert(str);
            });
        }
    </script>

</body>

</html>

注意：

  • 此处加载WFS时需要指定geometryName
  • OpenLayers控件的使用可以参考官方API，Modify控件在Select控件选择后跟随圆点拖拽就行

修改后的结果如下：

image-20220725002000932

6. 删除要素

使用OpenLayers，删除要素的流程：

  • 加载初始要素
  • 创建选择控件选择要素
  • 将选择的要素和信息写为XML
  • 序列化XML
  • 提交XML到服务器

核心代码如下：

// 服务配置，命名空间、图层、服务地址等
const geoserverData = {
    workSpaceName: 'topp',
    uri: 'http://www.openplans.org/topp',
    wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
    layer: 'tasmania_roads'
}

// 选择要素控件
let select = new ol.interaction.Select({
    layers: [vectorLayer],
    hitTolerance: 10
});
map.addInteraction(select);

document.querySelector('#delete').addEventListener('click', (event) => {
    let features = [];
    select.getFeatures().forEach(function (item, index, array) {
        features.push(item);
    });
    deleteWFS(features);
})

function deleteWFS(features) {
    let WFS = new ol.format.WFS();
    // 生成XML格式的WFS请求信息
    let transact_xml = WFS.writeTransaction(
        null, null, features,
        {
            srcName: 'EPSG:4326',
            featureNS: geoserverData.uri,
            featurePrefix: geoserverData.workSpaceName,
            featureType: [geoserverData.layer],
        }
    )
    // 将XML格式请求信息序列化为字符串格式
    transact_str = (new XMLSerializer()).serializeToString(transact_xml);
    // 使用Fetch将请求发送到后端
    fetch('http://localhost:8080/geoserver/wfs', {
        method: 'POST',
        body: transact_str,
        headers: {
            'Content-Type': 'text/xml'
        }
    }).then(res => res.text()).then(res => {
        console.log(res);
    });
}

完整代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <link rel="stylesheet"
        href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/css/ol.css" type="text/css">
    <script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.15.1/build/ol.js"></script>
    <style>
        html,
        body {
            height: 100%;
        }

        body {
            margin: 0;
            padding: 0;
        }

        #map {
            height: 100%;
        }
    </style>
</head>

<body>
    <button id="select">选择</button>
    <button id="delete">删除</button>
    <button id="exit">退出</button>
    <div id="map"></div>
    <script>
        const map = new ol.Map({
            target: 'map',
            layers: [],
            view: new ol.View({
                center: [147.01, -42.26],
                zoom: 8,
                projection: 'EPSG:4326'
            })
        });
        map.addLayer(new ol.layer.WebGLTile({
            source: new ol.source.OSM()
        }));
        const vectorLayer = new ol.layer.Vector({
            source: new ol.source.Vector({
                url: 'http://localhost:8080/geoserver/topp/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=topp:tasmania_roads&outputFormat=application/json',
                format: new ol.format.GeoJSON({
                    geometryName: 'the_geom'
                })
            }),
            style: new ol.style.Style({
                stroke: new ol.style.Stroke({
                    color: '#0000ff',
                    width: 2
                })
            })
        });
        map.addLayer(vectorLayer);

        document.querySelector('#select').addEventListener('click', (event) => {
            select.setActive(true);
        });
        document.querySelector('#exit').addEventListener('click', (event) => {
            select.setActive(false);
        });

        // 服务配置，命名空间、图层、服务地址等
        const geoserverData = {
            workSpaceName: 'topp',
            uri: 'http://www.openplans.org/topp',
            wfsURL: 'http://localhost:8080/geoserver/topp/ows?',
            layer: 'tasmania_roads'
        }

        // 选择要素控件
        let select = new ol.interaction.Select({
            layers: [vectorLayer],
            hitTolerance: 10
        });
        map.addInteraction(select);
        select.setActive(false);

        document.querySelector('#delete').addEventListener('click', (event) => {
            let features = [];
            select.getFeatures().forEach(function (item, index, array) {
                features.push(item);
            });
            deleteWFS(features);
        })

        function deleteWFS(features) {
            let WFS = new ol.format.WFS();
            // 生成XML格式的WFS请求信息
            let transact_xml = WFS.writeTransaction(
                null, null, features,
                {
                    srcName: 'EPSG:4326',
                    featureNS: geoserverData.uri,
                    featurePrefix: geoserverData.workSpaceName,
                    featureType: [geoserverData.layer],
                }
            )
            // 将XML格式请求信息序列化为字符串格式
            transact_str = (new XMLSerializer()).serializeToString(transact_xml);
            // 使用Fetch将请求发送到后端
            fetch('http://localhost:8080/geoserver/wfs', {
                method: 'POST',
                body: transact_str,
                headers: {
                    'Content-Type': 'text/xml'
                }
            }).then(res => res.text()).then(res => {
                let transactRes = WFS.readTransactionResponse(res);
                let str = transactRes.transactionSummary.totalInserted +
                    " totalInserted!, insertIds: " + transactRes.insertIds + "\n";
                str += transactRes.transactionSummary.totalUpdated + " totalUpdated!\n";
                str += transactRes.transactionSummary.totalDeleted + " totalDeleted!";
                alert(str);
            });
        }

    </script>

</body>

</html>

删除后的结果如下：

image-20220725005539772

7. 参考资料

[1]WFS - Introduction — OGC e-Learning 2.0.0 documentation (opengeospatial.github.io)

[2]WFS-简介 — OGC e-Learning 2.0.0 文档 (osgeo.cn)

[3]WFS参考 — GeoServer 2.19.x User Manual (osgeo.cn)

[4]使用.net c# 对GeoServer要素进行Insert和Delete操作_我是小怪兽-的博客-CSDN博客_c# geoserver

[5]开源GIS（十五）——openlayers通过geoserver中WFS删除要素_gis_morningsun的博客-CSDN博客

[6]OGC的网络要素服务（WFS）(持续更新。。。） - 知乎 (zhihu.com)

[7]OpenLayers v6.15.1 API - Class: WFS

[8]geoserver跨域 - 知乎 (zhihu.com)

posted @ 2022-07-25 01:06  当时明月在曾照彩云归  阅读(5079)  评论(5)  编辑  收藏  举报