Add provider properties configuration (#1079)

docs/source/configuration.rst

@@ -261,7 +261,7 @@ Below is an example of how to integrate system environment variables in pygeoapi
 Hierarchical collections
 ------------------------
 
-Collections defined in the the ``resources`` section are identified by the resource key.  The
+Collections defined in the ``resources`` section are identified by the resource key.  The
 key of the resource name is the advertised collection identifier.  For example, given the following:
 
 .. code-block:: yaml
@@ -297,6 +297,39 @@ The resulting collection will then be made available at http://localhost:5000/co
   the evolution of hierarchical collection extension specifications at OGC.
 
 
+Selective properties in feature and record providers
+----------------------------------------------------
+
+Providers defined in the ``providers`` section of a feature/record collection definition can support
+selective properties to return only a subset of the schema attributes. This allows to
+specialise the behavior of queryables and the GeoJSON's properties returned in the
+payload.
+
+For example, given the above example of the ``lakes`` collection a restriction on
+the schema properties returned by its provider can be defined with the following:
+
+.. code-block:: yaml
+
+  resources:
+    lakes:
+      ...
+      providers:
+        - type: feature
+          name: ...
+          data:
+            ...
+          properties:
+            - name
+
+Examples:
+
+.. code-block:: bash
+
+  curl https://example.org/collections/lakes/queryables  # only the name definition is returned
+  curl https://example.org/collections/lakes/items  # only the name attribute is returned in properties
+  curl https://example.org/collections/lakes/items/{item_id}  # only the name attribute is returned in properties
+
+
 Linked Data
 -----------