Question

对于交互式网络应用程序，我使用 Openlayers 4.6.5 与 Geoserver 2.13.0 。

希望使用 Geoserver WPS 启用动态处理用户选择的输入数据点。我已经使用SourceForge中的统计数据包扩展了WPS功能，并希望对选定点的集合运行KernelDensity分析。 KernelDensity 过程的结果应在我的地图中显示为栅格图层。

我正在使用Javascript的 fetch 功能向WPS发送XML请求。：

<wps:Execute version="1.0.0" service="WPS" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:wfs="http://www.opengis.net/wfs" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:gml="http://www.opengis.net/gml" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0 http://schemas.opengis.net/wps/1.0.0/wpsAll.xsd"><ows:Identifier>statistics:KernelDensity</ows:Identifier><wps:DataInputs><wps:Input><ows:Identifier>inputFeatures</ows:Identifier><wps:Data><wps:ComplexData mimeType="application/json"><![CDATA[{"type":"FeatureCollection","totalFeatures":2,"features":[{"type":"Feature","id":"alllocations.fid-57f369ef_1636c6c3947_-5ddb","geometry":{"type":"Point","coordinates":[100.330936,5.41626549]},"geometry_name":"geom","properties":{"idstorylocation":344,"idstory":27,"story":"HOUN","idlocation":203,"location_role":"reference","actions":"The walking stick left behind by young Dr Mortimer is of the sort which is called \"Penang Lawyer\".","name":"Penang ","country_today":"Malaysia","reference_to":"city","reality":"real","certainty":"good","accuracy":"high","county":"","state_country":"","city":"Penang","idcountry":298,"idpoints":99,"idperson":40,"initial":null,"lastname":"Mortimer","firstname":"James","nationality":null}},{"type":"Feature","id":"alllocations.fid-57f369ef_1636c6c3947_-5dda","geometry":{"type":"Point","coordinates":[100.330936,5.41626549]},"geometry_name":"geom","properties":{"idstorylocation":1519,"idstory":15,"story":"SILV","idlocation":203,"location_role":"reference","actions":"The stick of Fitzroy Simpson, which was a Penang-lawyer weighted with lead, was was just such a weapon as might, by repeated blows, have inflicted the terrible injuries to which the trainer had succumbed. ","name":"Penang ","country_today":"Malaysia","reference_to":"city","reality":"real","certainty":"good","accuracy":"high","county":"","state_country":"","city":"Penang","idcountry":298,"idpoints":99,"idperson":0,"initial":null,"lastname":null,"firstname":null,"nationality":null}}],"crs":{"type":"name","properties":{"name":"urn:ogc:def:crs:EPSG::4326"}}}]]></wps:ComplexData></wps:Data></wps:Input><wps:Input><ows:Identifier>kernelType</ows:Identifier><wps:Data><LiteralData>Quadratic</LiteralData></wps:Data></wps:Input><wps:Input><ows:Identifier>populationField</ows:Identifier><wps:Data><wps:LiteralData>icount</wps:LiteralData></wps:Data></wps:Input><wps:Input><ows:Identifier>searchRadius</ows:Identifier><wps:Data><wps:LiteralData>5</wps:LiteralData></wps:Data></wps:Input><wps:Input><ows:Identifier>cellSize</ows:Identifier><wps:Data><wps:LiteralData>20</wps:LiteralData></wps:Data></wps:Input><wps:Input><ows:Identifier>extent</ows:Identifier><wps:Data><wps:BoundingBoxData crs="EPSG:4326" dimension="2"><ows:LowerCorner>-180.0 -90.0</ows:LowerCorner><ows:UpperCorner>180.0 90.0</ows:UpperCorner></wps:BoundingBoxData></wps:Data></wps:Input></wps:DataInputs><wps:ResponseForm><wps:RawDataOutput mimeType="image/tiff"><ows:Identifier>result</ows:Identifier></wps:RawDataOutput></wps:ResponseForm></wps:Execute>

输入jsonstring是来自所选点数据的收集事件，输出应为 image / tiff 。

但是，我对如何从响应中获取 a）栅格以及b）将栅格作为图层添加到地图中感到茫然。

function calculateKernelDensity(jsonstring){

xml = createKernelDensityRequest(jsonstring);

fetch('http://localhost:8080/geoserver/Sherlock/wps', {
    method: 'POST',
    body: xml
})
// tried my luck with blob to use it later on as image layer
.then(function(response){
    var blob = response.blob(); 
    return blob;
})
.then(function(blob){
    console.log(blob.size + " " + blob.type);
});
// something here to put it as layer into the map...
};

我为基于矢量的请求（collectEvents，convexHull）做了一个非常类似的事情，并将response.json作为矢量要素添加到地图中，效果很好：

function collectEvents(jsonstring){

xml = createCollectEventsRequest(jsonstring);

fetch('http://localhost:8080/geoserver/Sherlock/wps',{
    method: 'POST',
    body: xml
})
.then(function(response){
    jsonresults = response.json();
    return jsonresults;
})
.then(function(jsonresults){
    jsonstring = JSON.stringify(jsonresults);
    results = new ol.format.GeoJSON({geometryName:'geom'}).readFeatures(jsonresults,{
        dataProjection: 'EPSG:4326',
        featureProjection: 'EPSG:3857'
    });
    vectorSource.clear(results);
    vectorSource.addFeatures(results);
});
};

我没有找到关于OpenLayers 4的任何好的文档以及如何将它与Geoserver WPS一起使用。关于使用Raster和Image源的API文档也没有任何帮助。我知道ol.source.ImageWMS，但是当我试图动态生成和显示栅格而不是从WMS中检索栅格时，这里没有选择。

有没有办法从WPS获取生成的光栅图像并将其显示在OpenLayers地图中？

Answer 1

根据this question的答案判断，无法在OpenLayers中直接显示GeoTiff，因为它使用浏览器的本机显示功能进行显示。

可能对您有用的一个选项是将WPS输出保存到GeoServer，然后使用WMS请求获取结果。有一个如何在GeoSolution's WPS training中执行此操作的示例。此answer也为此目的提及StoreCoverage进程，但我找不到任何其他引用。

Openlayers4

1 个答案: