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3.3. Web Feature Service (WFS)

The 1.0.0 and 1.1.0 WFS standards implemented in QGIS Server provide a HTTP interface to query geographic features from a QGIS project. A typical WFS request defines the QGIS project to use and the layer to query.

Specifications document according to the version number of the service:

Standardowe żądania dostarczane przez QGIS Server :

Zapytanie	Opis
GetCapabilities	Zwraca metadane XML zawierające informacje o serwerze
GetFeature	Returns a selection of features
DescribeFeatureType	Returns a description of feature types and properties
Transaction	Allows features to be inserted, updated or deleted

3.3.1. GetCapabilities

Standard parameters for the GetCapabilities request according to the OGC WFS 1.0.0 and 1.1.0 specifications:

Parametr	Wymagany	Opis
SERVICE	Tak	Name of the service (WFS)
REQUEST	Tak	Nazwa zapytania (GetCapabilities)
VERSION	Nie	Version of the service

In addition to the standard ones, QGIS Server supports the following extra parameters:

Parametr	Wymagany	Opis
MAP	Tak	Plik projektu QGIS

VERSION

This parameter allows to specify the version of the service to use. Available values for the VERSION parameter are:

1.0.0
1.1.0

If no version is indicated in the request, then 1.1.0 is used by default.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&...

3.3.2. GetFeature

Standard parameters for the GetFeature request according to the OGC WFS 1.0.0 and 1.1.0 specifications:

Parametr	Wymagany	Opis
SERVICE	Tak	Name of the service (WFS)
REQUEST	Tak	Name of the request (GetFeature)
VERSION	Nie	Version of the service
TYPENAME	Nie	Name of layers
FEATUREID	Nie	Filter the features by ids
OUTPUTFORMAT	Nie	Output Format
RESULTTYPE	Nie	Type of the result
PROPERTYNAME	Nie	Name of properties to return
MAXFEATURES	Nie	Maximum number of features to return
SRSNAME	Nie	Układ współrzędnych
FILTER	Nie	OGC Filter Encoding
BBOX	Nie	Map Extent
SORTBY	Nie	Sort the results

In addition to the standard ones, QGIS Server supports the following extra parameters:

Parametr	Wymagany	Opis
MAP	Tak	Plik projektu QGIS
STARTINDEX	Nie	Stronicowanie
GEOMETRYNAME	Nie	Type of geometry to return
EXP_FILTER	Nie	Expression filtering

TYPENAME

This parameter allows to specify layer names and is mandatory if FEATUREID is not set.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=GetFeature
&TYPENAME=countries

FEATUREID

This parameter allows to specify the ID of a specific feature and is formed like typename.fid,typename.fid,....

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&FEATUREID=countries.0,places.1

XML response:

<wfs:FeatureCollection xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:ows="http://www.opengis.net/ows" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:qgs="http://www.qgis.org/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.1.0/wfs.xsd http://www.qgis.org/gml http://192.168.1.15/qgisserver?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType&TYPENAME=countries,places&OUTPUTFORMAT=text/xml; subtype%3Dgml/3.1.1">
  <gml:boundedBy>
    ...
  </gml:boundedBy>
  <gml:featureMember>
    <qgs:countries gml:id="countries.1">
      ...
    </qgs:countries>
  </gml:featureMember>
  <gml:featureMember>
    <qgs:places gml:id="places.1">
      ...
    </qgs:places>
  </gml:featureMember>
</wfs:FeatureCollection>

OUTPUTFORMAT

This parameter may be used to specify the format of the response. If VERSION is greater or equal than 1.1.0, GML3 is the default format. Otherwise GML2 is used.

Available values are:

gml2
text/xml; subtype=gml/2.1.2
gml3
text/xml; subtype=gml/3.1.1
geojson
application/vnd.geo+json,
application/vnd.geo json
application/geo+json
application/geo json
application/json

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&FEATUREID=countries.0
&OUTPUTFORMAT=geojson

GeoJSON response:

{
    "type":"FeatureCollection",
    "bbox":[
        -180,
        -90,
        180,
        83.6236
    ],
    "features":[
        {
            "bbox":[
                -61.891113,
                16.989719,
                -61.666389,
                17.724998
            ],
            "geometry":{
                "coordinates":[
                    "..."
                ],
                "type":"MultiPolygon"
            },
            "id":"countries.1",
            "properties":{
                "id":1,
                "name":"Antigua and Barbuda"
            },
            "type":"Feature"
        }
    ]
}

RESULTTYPE

This parameter may be used to specify the kind of result to return. Available values are:

results: the default behavior
hits: returns only a feature count

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=GetFeature
&RESULTTYPE=hits
&...

PROPERTYNAME

This parameter may be used to specify a specific property to return. A property needs to be mapped with a TYPENAME or a FEATUREID:

Valid URL example:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&PROPERTYNAME=name
&TYPENAME=places

On the contrary, the next URL will return an exception:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&PROPERTYNAME=name
&TYPENAME=places,countries

<ServiceExceptionReport xmlns="http://www.opengis.net/ogc" version="1.2.0">
    <ServiceException code="RequestNotWellFormed">There has to be a 1:1 mapping between each element in a TYPENAME and the PROPERTYNAME list</ServiceException>
</ServiceExceptionReport>

MAXFEATURES

This parameter allows to limit the number of features returned by the request.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places
&MAXFEATURES=1000

Informacja

This parameter may be useful to improve performances when underlying vector layers are heavy.

SRSNAME

This parameter allows to indicate the response output Spatial Reference System as well as the BBOX CRS and has to be formed like EPSG:XXXX.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places
&SRSNAME=EPSG:32620

FILTER

This parameter allows to filter the response with the Filter Encoding language defined by the OGC Filter Encoding standard. For example:

http://localhost/qgisserver?
SERVICE=WFS&
REQUEST=GetFeature&
TYPENAME=places&
FILTER=<Filter><PropertyIsEqualTo><PropertyName>name</PropertyName><Literal>Paris</Literal></PropertyIsEqualTo></Filter>

In case of multiple typenames, filters have to be enclosed in parentheses:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places,countries
&FILTER=(<Filter><PropertyIsEqualTo><PropertyName>name</PropertyName><Literal>Paris</Literal></PropertyIsEqualTo></Filter>)(<Filter><PropertyIsEqualTo><PropertyName>name</PropertyName><Literal>France</Literal></PropertyIsEqualTo></Filter>)

Filter features that intersect with a polygon:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&VERSION=1.1.0
&TYPENAME=places
&FILTER=<Filter xmlns="http://www.opengis.net/ogc">
           <Intersects>
               <PropertyName>geometry</PropertyName>
               <Polygon xmlns="http://www.opengis.net/gml" srsName="EPSG:4326">
                   <exterior>
                       <LinearRing>
                           <posList>
                               -0.6389 42.5922
                               10.2683 51.9106
                               14.5196 41.0320
                               -0.6389 42.5922
                           </posList>
                       </LinearRing>
                   </exterior>
               </Polygon>
           </Intersects>
       </Filter>

BBOX

This parameter allows to specify the map extent with units according to the current CRS. Coordinates have to be separated by a comma.

The SRSNAME parameter may specify the CRS of the extent. If not specified, the CRS of the layer is used.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places
&BBOX=-11.84,42.53,8.46,50.98

The FEATUREID parameter cannot be used with the BBOX. Any attempt will result in an exception:

<ServiceExceptionReport xmlns="http://www.opengis.net/ogc" version="1.2.0">
  <ServiceException code="RequestNotWellFormed">FEATUREID FILTER and BBOX parameters are mutually exclusive</ServiceException>
</ServiceExceptionReport>

SORTBY

This parameter allows to sort resulting features according to property values and has to be formed like propertyname SORTRULE.

Available values for SORTRULE in case of descending sorting:

D
+D
DESC
+DESC

Available values for SORTRULE in case of ascending sorting:

A
+A
ASC
+ASC

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places
&PROPERTYNAME=name
&MAXFEATURES=3
&SORTBY=name DESC

The corresponding result:

<wfs:FeatureCollection xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:ows="http://www.opengis.net/ows" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:qgs="http://www.qgis.org/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.1.0/wfs.xsd http://www.qgis.org/gml http://192.168.1.15/qgisserver?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType&TYPENAME=places&OUTPUTFORMAT=text/xml; subtype%3Dgml/3.1.1">
    <gml:boundedBy>
        ...
    </gml:boundedBy>
    <gml:featureMember>
        <qgs:places gml:id="places.90">
            <qgs:name>Zagreb</qgs:name>
        </qgs:places>
    </gml:featureMember>
    <gml:featureMember>
        <qgs:places gml:id="places.113">
            <qgs:name>Yerevan</qgs:name>
        </qgs:places>
    </gml:featureMember>
    <gml:featureMember>
        <qgs:places gml:id="places.111">
            <qgs:name>Yaounde</qgs:name>
        </qgs:places>
    </gml:featureMember>
</wfs:FeatureCollection>

GEOMETRYNAME

This parameter can be used to specify the kind of geometry to return for features. Available values are:

zasięg
centroid
none

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=GetFeature
&GEOMETRYNAME=centroid
&...

STARTINDEX

This parameter is standard in WFS 2.0, but it’s an extension for WFS 1.0.0.

Actually, it can be used to skip some features in the result set and in combination with MAXFEATURES, it provides the ability to page through results.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=GetFeature
&STARTINDEX=2
&...

EXP_FILTER

This parameter allows to filter the response with QGIS expressions. The ; character is used to separate filters in case of multiple typenames.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&REQUEST=GetFeature
&TYPENAME=places,countries
&EXP_FILTER="name"='Paris';"name"='France'

3.3.3. DescribeFeatureType

Standard parameters for the DescribeFeatureType request according to the OGC WFS 1.0.0 and 1.1.0 specifications:

Parametr	Wymagany	Opis
SERVICE	Tak	Name of the service (WFS)
REQUEST	Tak	Name of the request (DescribeFeatureType)
VERSION	Nie	Version of the service
OUTPUTFORMAT	Nie	Format of the response
TYPENAME	Nie	Name of layers

In addition to the standard ones, QGIS Server supports the following extra parameters:

Parametr	Wymagany	Opis
MAP	Tak	Plik projektu QGIS

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=DescribeFeatureType
&TYPENAME=countries

Output response:

<schema xmlns:ogc="http://www.opengis.net/ogc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:qgs="http://www.qgis.org/gml" xmlns:gml="http://www.opengis.net/gml" targetNamespace="http://www.qgis.org/gml" version="1.0" elementFormDefault="qualified">
  <import schemaLocation="http://schemas.opengis.net/gml/3.1.1/base/gml.xsd" namespace="http://www.opengis.net/gml"/>
  <element type="qgs:countriesType" substitutionGroup="gml:_Feature" name="countries"/>
  <complexType name="countriesType">
    <complexContent>
      <extension base="gml:AbstractFeatureType">
        <sequence>
          <element minOccurs="0" type="gml:MultiPolygonPropertyType" maxOccurs="1" name="geometry"/>
          <element type="long" name="id"/>
          <element nillable="true" type="string" name="name"/>
        </sequence>
      </extension>
    </complexContent>
  </complexType>
</schema>

3.3.4. Transaction

This request allows to update, delete or add one or several features thanks to a XML document. The delete action may be achieved with a POST request as well as with the OPERATION parameter while the add and the update operations may be achieved through POST request only.

Standard parameters for the Transaction request according to the OGC WFS 1.0.0 and 1.1.0 specifications:

Parametr	Wymagany	Opis
SERVICE	Tak	Name of the service (WFS)
REQUEST	Tak	Name of the request (Transaction)
VERSION	Nie	Version of the service
FILTER	Nie	OGC Filter Encoding
BBOX	Nie	Map Extent
FEATUREID	Nie	Filter the features by ids
TYPENAME	Nie	Name of layers

In addition to the standard ones, QGIS Server supports the following extra parameters:

Parametr	Wymagany	Opis
MAP	Tak	Plik projektu QGIS
OPERATION	Nie	Specify the operation
EXP_FILTER	Nie	Expression filtering

OPERATION

This parameter allows to delete a feature without using a POST request with a dedicated XML document.

Przykład URL:

http://localhost/qgisserver?
SERVICE=WFS
&VERSION=1.1.0
&REQUEST=Transaction
&OPERATION=DELETE
&FEATUREID=24

Informacja

FEATUREID, BBOX and FILTER parameters are mutually exclusive and prioritized in this order.

Add features

POST request example:

wget --post-file=add.xml "http://localhost/qgisserver?SERVICE=WFS&REQUEST=Transaction"

with the add.xml document:

<?xml version="1.0" encoding="UTF-8"?>
<wfs:Transaction service="WFS" version="1.0.0" xmlns:wfs="http://www.opengis.net/wfs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ogc="http://www.opengis.net/ogc" xmlns="http://www.opengis.net/wfs" updateSequence="0" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-capabilities.xsd" xmlns:gml="http://www.opengis.net/gml"  xmlns:ows="http://www.opengis.net/ows">
  <wfs:Insert idgen="GenerateNew">
    <qgs:places>
      <qgs:geometry>
        <gml:Point srsDimension="2" srsName="http://www.opengis.net/def/crs/EPSG/0/4326">
          <gml:coordinates decimal="." cs="," ts=" ">-4.6167,48.3833</gml:coordinates>
        </gml:Point>
      </qgs:geometry>
      <qgs:name>Locmaria-Plouzané</qgs:name>
    </qgs:places>
  </wfs:Insert>
</wfs:Transaction>

Update features

POST request example:

wget --post-file=update.xml "http://localhost/qgisserver?SERVICE=WFS&REQUEST=Transaction"

with the update.xml document:

<?xml version="1.0" encoding="UTF-8"?>
<wfs:Transaction service="WFS" version="1.0.0" xmlns:wfs="http://www.opengis.net/wfs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ogc="http://www.opengis.net/ogc" xmlns="http://www.opengis.net/wfs" updateSequence="0" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-capabilities.xsd" xmlns:gml="http://www.opengis.net/gml"  xmlns:ows="http://www.opengis.net/ows">
    <wfs:Update typeName="places">
      <wfs:Property>
          <wfs:Name>name</wfs:Name>
          <wfs:Value>Lutece</wfs:Value>
      </wfs:Property>
      <ogc:Filter>
          <ogc:FeatureId fid="24"/>
      </ogc:Filter>
    </wfs:Update>
</wfs:Transaction>

Usuń obiekty

POST request example:

wget --post-file=delete.xml "http://localhost/qgisserver?SERVICE=WFS&REQUEST=Transaction"

with the delete.xml document:

<?xml version="1.0" encoding="UTF-8"?>
<wfs:Transaction service="WFS" version="1.0.0" xmlns:wfs="http://www.opengis.net/wfs" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ogc="http://www.opengis.net/ogc" xmlns="http://www.opengis.net/wfs" updateSequence="0" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/WFS-capabilities.xsd" xmlns:gml="http://www.opengis.net/gml"  xmlns:ows="http://www.opengis.net/ows">
    <wfs:Delete typeName="places">
        <ogc:Filter>
            <ogc:FeatureId fid="24"/>
        </ogc:Filter>
    </wfs:Delete>
</wfs:Transaction>