diff --git a/docs/user_manual/working_with_vector/editing_geometry_attributes.rst b/docs/user_manual/working_with_vector/editing_geometry_attributes.rst index 839b3acdb31..d46514c34c9 100644 --- a/docs/user_manual/working_with_vector/editing_geometry_attributes.rst +++ b/docs/user_manual/working_with_vector/editing_geometry_attributes.rst @@ -1177,6 +1177,16 @@ The |addPart| :sup:`Add Part` can also be used to add a geometry to a geometryle feature. First, select the feature in the attribute table and digitize the new geometry with the |addPart| :sup:`Add Part` tool. +.. note:: **Order of vertices in polygon parts** + + Unlike the OGC standards, QGIS doesn't constrain vertices + of the exterior boundary of a polygon feature to be ordered counterclockwise. + Thus, you can find both directions in a layer. + However, every parts of the same multipolygon feature + will have their outer vertices ordered following the same direction. + + You can however use the :ref:`qgisforcerhr` algorithm to constrain features of a layer + to have vertices of their outer boundaries ordered in the clockwise direction. .. index:: single: Digitizing tools; Delete Part @@ -1199,16 +1209,32 @@ To delete a part, simply click within the target part. Add Ring -------- -You can create ring polygons using the |addRing| -:sup:`Add Ring` icon in the toolbar. This means that inside an existing area, it -is possible to digitize further polygons that will occur as a 'hole', so -only the area between the boundaries of the outer and inner polygons remains -as a ring polygon. +You can create ring polygons using the |addRing| :sup:`Add Ring` icon in the toolbar. +This means that inside an existing area, it is possible to digitize further polygons +that will occur as a 'hole', so only the area between the boundaries +of the outer and inner polygons remains as a ring polygon. + +To add a ring: + +#. Select the feature(s) to modify +#. Activate the |addRing| :sup:`Add Ring` tool +#. Draw a polygon within the selected geometries, + using the aforementioned :ref:`techniques `. + A hole appears in the selected geometries. +#. If no geometry is selected when the ring is drawn, + then a hole is added to each of the polygons the ring is drawn over. + +.. note:: **Order of vertices in polygon rings** -.. FixMe: I think this tool should behave as below -.. Like many digitizing tools, the |addRing| :sup:`Add Ring` tool adds ring to all -.. selected features if any, otherwise all overlapping features are pierced. + Unlike the OGC standards, QGIS doesn't constrain vertices + of the exterior boundary of a polygon feature to be ordered counterclockwise. + Thus, you can find both directions in a layer. + However, every rings of the same (multi)polygon feature + will have their vertices ordered in the opposite direction to the outer boundary's. + You can however use the :ref:`qgisforcerhr` algorithm to constrain features of a layer + to have vertices of their outer boundaries ordered in the clockwise direction, + and vertices of their interior rings ordered in the counter-clockwise direction. .. index:: single: Digitizing tools; Fill Ring