Spatial Filter/OGC Service Type Matrix
Spatial Filter Name Spatial Filter Supported for GetFeature for all Web Feature Services? Spatial Filter Supported for GetMap for the Web Map Service?
Intersect by Bounding Box Yes Yes
Intersect by Bounding Polygon Yes No
Entirely within Distance from a Point Yes No

In addition to the spatial filters listed above, we intend to eventually support Intersect by Line and Intersect by Point. For the time being, “Intersect by Point” can be faked by using “Entirely within Distance from a Point”, where the distance is set to zero. See the example farther below.

For any GetFeature request, one or more input spatial filters are supported.

For a GetMap request, a single bounding box spatial filter is required.

For additional information about OGC compliant spatial filters, please visit http://www.opengeospatial.org/standards/filter

For these web services, spatial filters must be expressed using the version 1.0 filter encoding.


Spatial Filter Extent Limit
The total extent defined by any spatial filter cannot exceed 10,100,000,000 square meters (approximately 3,900 square miles or 2,500,000 acres).


Spatial Filter Descriptions and Examples
Intersect by Bounding Box Back to Top
All features that share any coincidence with the bounding box are returned.

Bounding Box - BBOX Shorthand example:
BBOX=-114.006,32.1823,-113.806,32.2823

Bounding Box - Intersect by Rectangle example:
Filter=<Filter><BBOX><PropertyName>Geometry</PropertyName><Box srsName='EPSG:4269'>
     <coordinates>-86.46878,40.56448 -86.45282,40.57646</coordinates></Box></BBOX></Filter>

Intersect by Bounding Polygon Back to Top
All features that share any coincidence with the bounding polygon are returned.

Intersect by Bounding Polygon example:
Filter=<Filter><Intersect><PropertyName>Geometry</PropertyName><gml:Polygon>
     <gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>-88.0865046533,37.5555143852
     -88.0860204771,37.5600435404 -88.0782858287,37.5595392364 -88.0787704736,37.5550101113
     -88.0865046533,37.5555143852</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs>
     </gml:Polygon></Intersect></Filter>

Entirely within Distance from a Point Back to Top
All features that lie entirely within a distance from a point are returned.

Entirely within Distance of a Point example:
Filter=<Filter><DWithin><PropertyName>Geometry</PropertyName><gml:Point>
     <gml:coordinates>-91.22,38.46</gml:coordinates></gml:Point><Distance%20units='m'>600</Distance>
     </DWithin></Filter>

Workaround to achieve Intersect by Point (set distance to 0) example:
Filter=<Filter><DWithin><PropertyName>Geometry</PropertyName><gml:Point>
     <gml:coordinates>-91.22,38.46</gml:coordinates></gml:Point><Distance%20units='m'>0</Distance>
     </DWithin></Filter>


Spatial Filter Spatial Reference System
Web Feature Services
An output spatial reference system is inherent to each web feature service. In other words, each web feature service corresponds to one and only one output spatial reference system. For a web feature service there is no explicit parameter for the output spatial reference system, however the UTM web feature service does take an SRSName parameter to indicate which UTM zone is desired.

For a spatial filter expressed using the BBOX tag, the coordinates must be in the same spatial reference system as the inherent output spatial reference system.

For a spatial filter expressed using a GML filter shape specification, the coordinates must be in the same spatial reference system as the underlying source data, i.e. NAD 83 Geographic for the Soil Data Mart database.

Web Map Service
For the web map service, an explicit output spatial reference system is required, and the spatial filter must be expressed using the BBOX tag. The bounding box coordinates must be in the same spatial reference system as the output spatial reference system.