GeoJSON输出格式

默认的GeoJSON输出使用WFS GeoJSON编码机制，生成固定的输出，但是可以使用FreeMarker模板自定义输出。Geoserver将查找遵循为html输出定义的相同规则的json模板，但模板文件必须命名为appending _json 更改为通常的名称，如下所示：

  • header_json.ftl

  • content_json.ftl

  • footer_json.ftl

此外，与html不同的是，必须提供所有三个模板文件。在多层请求的情况下，Geoserver将按照以下方式运行：

  • 内容模板将按照通常的规则进行搜索；

  • 因为GeoJSON没有默认模板，所以页眉和页脚将在 templates 目录；

  • 没有内容模板的特性将使用常规GeoJSON编码以及自定义编码进行编码。

以下是每种类型的json模板示例。

这个 头json模板 ：：

{
 "header":"this is the header",
 "type":"FeatureCollection",
 "features":[

这个 页脚json模板 ：：

 ],
 "footer" : "this is the footer"
}

这个 内容json模板 ：：

 <#list features as feature>
{
 "content" : "this is the content",
 "type": "Feature",
 "id" : "${feature.fid}",
 <#list feature.attributes as attribute>
 <#if attribute.isGeometry>
 "geometry": ${geoJSON.geomToGeoJSON(attribute.rawValue)},
 </#if>
 </#list>
 "properties": {
 <#list feature.attributes?filter(a -> !a.isGeometry) as attribute>
 "${attribute.name}": "${attribute.value}"
 <#if attribute_has_next>
 ,
 </#if>
 </#list>
 }
}
<#if feature_has_next>
,
</#if>
</#list>

从内容模板中可以看到，一个新的静态模型 geoJSON ，其中包含 geomToGeoJSON 方法已提供。它可以通过以下方式将geometry属性的原始值传递给有效的geoJSON几何体来对其进行编码： ${{geoJSON.geomToGeoJSON(attribute.rawValue)}} .

将上述模板放置在tigerúu roads图层的目录中并发出此请求：

http://localhost:8080/geoserver/tiger/wms?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&FORMAT=application/json&TRANSPARENT=true&QUERY_LAYERS=tiger:tiger_roads&LAYERS=tiger:tiger_roads&exceptions=application/vnd.ogc.se_inimage&INFO_FORMAT=application/json&FEATURE_COUNT=50&X=50&Y=50&SRS=EPSG:4326&STYLES=&WIDTH=101&HEIGHT=101&BBOX=-73.96894311918004,40.78191518783569,-73.96460866941197,40.78624963760376

将产生输出：

{
  "header":"this is the header",
  "type":"FeatureCollection",
  "features":[
     {
        "content":"this is the content",
        "type":"Feature",
        "id":"tiger_roads.7752",
        "geometry":{
           "type":"MultiLineString",
           "coordinates":[
              [
                 [
                    -73.9674,
                    40.7844
                 ],
                 [
                    -73.9642,
                    40.7832
                 ],
                 [
                    -73.9628,
                    40.7813
                 ]
              ]
           ]
        },
        "properties":{
           "CFCC":"A41",
           "NAME":"85th St Transverse"
        }
     }
  ],
  "footer":"this is the footer"
}

在移动收割台时_json.ftl格式和页脚_json.ftl格式进入templates目录并对tiger ny层组执行以下请求：

http://localhost:8080/geoserver/wms?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&FORMAT=application/json&TRANSPARENT=true&QUERY_LAYERS=tiger-ny&LAYERS=tiger-ny&exceptions=application/vnd.ogc.se_inimage&INFO_FORMAT=application/json&FEATURE_COUNT=50&X=50&Y=50&SRS=EPSG:4326&STYLES=&WIDTH=101&HEIGHT=101&BBOX=-74.01161170018896,40.70833468424098,-74.00944447530493,40.710501909125014

将返回以下结果：

{
  "header":"this is the header",
  "type":"FeatureCollection",
  "features":[
     {
        "type":"Feature",
        "id":"giant_polygon.1",
        "geometry":{
           "type":"MultiPolygon",
           "coordinates":[
              [
                 [
                    [
                       -180,
                       -90
                    ],
                    [
                       -180,
                       90
                    ],
                    [
                       180,
                       90
                    ],
                    [
                       180,
                       -90
                    ],
                    [
                       -180,
                       -90
                    ]
                 ]
              ]
           ]
        },
        "properties":{
           "@featureType":"giant_polygon",
           "the_geom":{
              "type":"MultiPolygon",
              "coordinates":[
                 [
                    [
                       [
                          -180,
                          -90
                       ],
                       [
                          -180,
                          90
                       ],
                       [
                          180,
                          90
                       ],
                       [
                          180,
                          -90
                       ],
                       [
                          -180,
                          -90
                       ]
                    ]
                 ]
              ]
           }
        }
     },
     {
        "content":"this is the content",
        "type":"Feature",
        "id":"tiger_roads.7672",
        "geometry":{
           "type":"MultiLineString",
           "coordinates":[
              [
                 [
                    -74.0108,
                    40.7093
                 ],
                 [
                    -74.0105,
                    40.7096
                 ]
              ]
           ]
        },
        "properties":{
           "CFCC":"A41",
           "NAME":"Broadway"
        }
     },
     {
        "type":"Feature",
        "id":"poi.3",
        "geometry":{
           "type":"Point",
           "coordinates":[
              -74.01053,
              40.709387
           ]
        },
        "properties":{
           "@featureType":"poi",
           "the_geom":{
              "type":"Point",
              "coordinates":[
                 -74.01053,
                 40.709387
              ]
           },
           "NAME":"art",
           "THUMBNAIL":"pics/22037856-Ti.jpg",
           "MAINPAGE":"pics/22037856-L.jpg"
        }
     }
  ],
  "footer":"this is the footer"
}

可以看到，json输出由Tiger_Roads特性的Content_json.ftl传递的输出和其他特性的正常输出混合而成，而页眉和页脚分别位于顶部和底部。

Previous: HTML输出格式
Next: 栅格GetFeatureInfo响应自定义