Openlayers4中Geoserver WPS的显示光栅结果

Question

对于交互式web应用程序，我使用Open层4.6.5和Geoserver 2.13.0。

希望通过使用Geoserver WPS对用户选择的输入数据点启用动态处理。我已经用来自SourceForge的统计软件包扩展了WPS功能，并希望对所选点的集合运行KernelDensity分析。KernelDensity处理的结果将在我的地图中显示为光栅层。

我正在使用Javascript的提取功能向WPS发送一个请求。

<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是收集的事件从选定的点数据，输出应该是图像/tiff。

然而，我不知道如何将a)从响应中获取光栅，以及( b)光栅作为图层进入我的地图.。

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...
};  

对于基于向量的请求(collectEvents、convexHull)，我做了一件非常类似的事情，并将response.json作为矢量特性添加到地图中，这很好：

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);
});
};

我找不到任何关于OpenLayers 4的好文档，也找不到如何与Geoserver一起使用它。API文档对于使用Raster和Image资源也没有任何帮助。我确实了解ol.source.ImageWMS，但是由于我试图动态地生成和显示光栅，而不是从WMS中检索光栅，所以这里没有选择。

有没有办法从WPS中获取生成的光栅图像并在OpenLayers地图上显示？

Answer 1

从这个问题的回答来看，不可能在OpenLayers中直接显示GeoTiff，因为它使用浏览器的本机显示功能来进行显示。

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。在GeoS卷积的WPS训练中有一个如何做到这一点的例子。这个回答也为此目的提到了StoreCoverage过程，但是我找不到任何其他的引用。