。1.2WFS簡介
Web要素服務(WFS)返回的是要素級的GML編碼,并提供對要素的增加、修改、刪除等事務操作,是對Web地圖服務的進一步深入。OGC Web要素服務允許客戶端從多個Web要素服務中取得使用地理標記語言(GML)編碼的地理空間數據,這個遠東定義了五個操作:GetCapabilites返回Web要素服務性能描述文檔(用xml描述);DescribeFeatureType返回描述可以提供服務的任何要素結構的XML文檔;GetFeature為一個獲取要素實例的請求提供服務;Transaction為事務請求提供服務;LockFeature處理在一個事務期間對一個或多個要素類型實例上鎖的請求。
GeoServer官網上對其WFS規范的描述地址為http://docs.geoserver.org/stable/en/user/services/wfs/index.html。
2.WMS請求規范詳解
2.1GetCapabitities(返回服務級元數據)
URL例子:
http://localhost:8680/geoserver/wms?service=wms&version=1.1.1&request=GetCapabilities。
參數意義:
![]()
返回結果:
其返回結果為一個描述性XML文檔,包含了以下三個要素:
![]()
2.2GetMap(獲取影像)
URL例子:
http://localhost:8680/geoserver/urbanlayer/wms?LAYERS=urbanlayer%3ADIJI&STYLES=&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&SRS=EPSG%3A3857&BBOX=10008053.503544,5274522.8578226,10039584.01305,5292493.614536&WIDTH=579&HEIGHT=330。
參數意義:
![]()
這里對返回的格式(format)有如下選擇:
返回結果:
注意:此請求同樣支持XML格式請求,如下:
2.3GetFeatureInfo(返回要素信息)
URL例子:
http://localhost:8680/geoserver/urbanlayer/wms?REQUEST=GetFeatureInfo&EXCEPTIONS=application%2Fvnd.ogc.se_xml&BBOX=10008053.503544%2C5274522.857823%2C10039584.01305%2C5292493.614536&SERVICE=WMS&INFO_FORMAT=text/plain&QUERY_LAYERS=urbanlayer%3ADIJI&FEATURE_COUNT=50&Layers=urbanlayer%3ADIJI&WIDTH=579&HEIGHT=330&format=image%2Fpng&styles=&srs=EPSG%3A3857&version=1.1.1&x=315&y=147。
參數意義:
這里對返回的文本格式(info_format)有如下選擇:
返回結果(忽略中文亂碼):
![]()
3.WFS請求規范
3.1GetCapabilities(返回服務描述文檔)
URL例子:
http://localhost:8680/geoserver/wfs?service=wfs&version=1.1.0&request=GetCapabilities。
參數意義:
返回結果:
返回的結果為描述性XML,包含以下五個主要部分:
3.2DescribeFeatureType(返回圖層描述信息)
URL例子:
http://localhost:8680/geoserver/urbanlayer/ows?service=wfs&version=1.0.0&request=DescribeFeatureType&typeName=DIJI。
參數意義:
返回結果:
3.3GetFeature(獲取圖層要素)
3.3.1GET查詢
這里首先給出一個例子:
http://localhost:8080/eGovaGISV14//home/gis/PRoxy.htm?http://192.168.101.14/geoserver/urbanlayer/wfs?request=GetFeature&version=1.1.0&typename=jianfudanhistory&Filter=%3CFilter%20xmlns:ogc=%22http://www.opengis.net/ogc%22%20xmlns:gml=%22http://www.opengis.net/gml%22%3E%3CIntersects%3E%20%3CPropertyName%3Ethe_geom%3C/PropertyName%3E%20%3Cgml:Envelope%20srsName=%22EPSG:4326%22%3E%09%20%3Cgml:lowerCorner%3E120.1762573834964%2030.280899047851562%3C/gml:lowerCorner%3E%20%09%20%3Cgml:upperCorner%3E120.18999029365265%2030.294631958007812%3C/gml:upperCorner%3E%20%3C/gml:Envelope%3E%3C/Intersects%3E%3C/Filter%3E&outputformat=json。
此請求常見的參數有:typeNames,featureID,propertyName,Filter, count, sortBy。其中Filter參數最為重要,主要負責進行選擇過濾。關于Filter的具體描述可參考:http://docs.geoserver.org/stable/en/user/filter/function.html。
返回結果為:
{"type":"FeatureCollection","features":[{"type":"Feature","id":"jianfudan.322","geometry":{"type":"Multipolygon","coordinates":[[[[30.276436000822056,120.20021],[30.275750000822033,120.20021],[30.22768400082126,120.22562],[30.245537000821543,120.17343000000001],[30.276436000822056,120.20021]]]]},"geometry_name":"the_geom","properties":{"limitid":71,"displayorder":null,"regionid":3,"validfromdate":"2016-05-15Z","validtodate":"2016-06-14Z","validflag":1,"media":null,"shape_length":null,"shape_area":null,"graphicid":322,"regionname":"江干區","eventtypes":null,"otherrequest":null,"limitname":"上報區域71"}},{"type":"Feature","id":"jianfudan.318","geometry":{"type":"MultiPolygon","coordinates":[[[[30.26407600082185,120.19668600000001],[30.26407600082185,120.196434],[30.262875000821833,120.20785],[30.24708200082157,120.203896],[30.255150000821704,120.187164],[30.26407600082185,120.19668600000001]]]]},"geometry_name":"the_geom","properties":{"limitid":72,"displayorder":null,"regionid":3,"validfromdate":"2016-05-04Z","validtodate":"2016-06-03Z","validflag":1,"media":"http://172.18.6.197:8081/MediaRoot/null/20160505/72/84989ee1-9bab-4640-8f24-4a7381f1c4e8/機票預訂.png","shape_length":null,"shape_area":null,"graphicid":318,"regionname":"江干區","eventtypes":"亂搭亂建,暴露垃圾,積存垃圾渣土,路面不潔,河道不潔(含溝渠、湖面)","otherrequest":"測試","limitname":"上報區域72"}}],"crs":{"type":"EPSG","properties":{"code":"4490"}}}
3.3.1.1點查詢Filter
<Filter xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml">
<Intersects>
<PropertyName>the_geom</PropertyName>
<gml:Envelope srsName="EPSG:4326">
<gml:lowerCorner>120.15336460382575 30.2743621901609</gml:lowerCorner>
<gml:upperCorner>120.167097513982 30.28809510031715</gml:upperCorner>
</gml:Envelope>
</Intersects>
</Filter>
3.3.1.2自定義多邊形查詢Filter
<Filter xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml">
<Intersects>
<PropertyName>the_geom</PropertyName>
<gml:MultiPolygon srsName="EPSG:4326">
<gml:polygonMember>
<gml:Polygon>
<gml:outerBoundaryIs>
<gml:LinearRing>
<gml:coordinates xmlns:gml="http://www.opengis.net/gml" decimal="." cs="," ts="">
120.15677,30.2557 120.15677,30.26351 120.16833,30.26351 120.16833,30.2557 120.15677,30.2557
</gml:coordinates>
</gml:LinearRing>
</gml:outerBoundaryIs>
</gml:Polygon>
</gml:polygonMember>
</gml:MultiPolygon>
</Intersects>
</Filter>
3.3.2Post查詢
因為GET請求的數據量大小在4kb以內,所以Post為更常用的方法。以下為一個具體的例子:
![]()
其中直接發送的為一個XML文件,其Filter中可以填寫的內容和GET中的Filter一樣。
具體內容如下:
<?xml version='1.0' encoding='GBK'?><wfs:GetFeature service='WFS' version='1.0.0' outputFormat='JSON'
xmlns:wfs='http://www.opengis.net/wfs'
xmlns:ogc='http://www.opengis.net/ogc'
xmlns:gml='http://www.opengis.net/gml' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://www.opengis.net/wfshttp://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd'>
<wfs:Query typeName='cell'>
<wfs:PropertyName>the_geom</wfs:PropertyName>
<wfs:PropertyName>test1</wfs:PropertyName>
<ogc:Filter>
<Or>
<PropertyIsEqualTo><PropertyName>test1</PropertyName><Literal>valuetest1</Literal></PropertyIsEqualTo>
<PropertyIsEqualTo><PropertyName>test2</PropertyName><Literal>valuetest2</Literal></PropertyIsEqualTo>
</Or>
</ogc:Filter>
</wfs:Query>
</wfs:GetFeature>
3.4 Transaction(編輯要素)
該方法支持對要素的增刪改。這里直接給出Post請求中發送的XML組織格式:
3.4.1添加要素
<wfs:Transaction service="WFS" version="1.0.0" outputFormat="GML2" xmlns:opengis="http://www.cetusOpengis.com" xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd"> <wfs:Insert handle="someprj1"> <opengis:someprj> <opengis:the_geom> <gml:Point srsName="http://www.opengis.net/gml/srs/epsg.xml#3395" > <gml:coordinates decimal="." cs="," ts="">13404701.212,3850391.781</gml:coordinates> </gml:Point> </opengis:the_geom> <opengis:ssds>13</opengis:ssds> <opengis:QQybh>12</opengis:qqybh> <opengis:status>0</opengis:status> </opengis:someprj> </wfs:Insert> </wfs:Transaction>
3.4.2修改要素
<wfs:Transaction service="WFS" version="1.0.0" outputFormat="GML2" xmlns:opengis="http://www.cetusOpengis.com" xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd"> <wfs:Update typeName="opengis:qqyproject"> <wfs:Property> <wfs:Name>qqybh</wfs:Name> <wfs:Value>12</wfs:Value> </wfs:Property> <ogc:Filter> <ogc:PropertyIsEqualTo> <ogc:PropertyName>qqybh</ogc:PropertyName> <ogc:Literal>0</ogc:Literal> </ogc:PropertyIsEqualTo> </ogc:Filter> </wfs:Update> </wfs:Transaction>
3.4.3刪除要素
<wfs:Transaction service="WFS" version="1.0.0" outputFormat="GML2" xmlns:opengis="http://www.cetusOpengis.com" xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-basic.xsd"> <wfs:Delete typeName="opengis:qqyproject"> <ogc:Filter> <ogc:PropertyIsLessThan> <ogc:PropertyName>qqybh</ogc:PropertyName> <ogc:Literal>12</ogc:Literal> </ogc:PropertyIsLessThan> <ogc:PropertyIsGreaterThan> <ogc:PropertyName>qqybh</ogc:PropertyName> <ogc:Literal>0</ogc:Literal> </ogc:PropertyIsGreaterThan> </ogc:Filter> </wfs:Delete> </wfs:Transaction>
4.總結
a.動態出圖可以使用WMS中的GetMap請求。
b.矢量查詢可以使用WFS中的GetFeature請求。
c.要素編輯可以使用WFS中的Transaction請求。
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