By David Crowther
Question:
How can I create holes within an existing spatial object?
Answer:
You may have a polygon layer where you wish to remove parts of it over time e.g. editing a Section 106 polygon to remove certain areas as a development progresses.
These types of edits can easily be done within a desktop GIS such as QGIS.
Once you have opened the source file e.g. a SQL Database Table, make the layer editable and then open the Advanced Digitising Toolbar.
From the Advanced Digitising Toolbar choose the ADD RING tool and draw an area to cut out of the existing polygon feature.
Once the Ring has been digitised the existing polygon will be updated with the area now removed.
Save the change to the source file and your data will be updated for all users e.g. webGIS users.