Donut parcels need to be located and linked correctly to avoid topology problems occurring in Landonline.

Donut parcels are parcels inside parcels that are not connected by boundaries of the same topology. They are two independent parcel rings. An example is an island in the middle of a lake. The island is the inner parcel ring with the lake being the outer parcel ring.

Surveys may indirectly incorporate donut parcels by virtue of exclusion. The subject parcels may border an existing parcel (or parcels) completely, which is not subject to the survey.

Locating Donut Parcels

You need to spatially locate inner rings caused by donut parcels within their parent ring. Parcel rings must follow a specific boundary direction convention in Landonline. That is, the ‘inside’ of the parcel must always be on the right hand side of a boundary. This means that outer rings are in a clockwise direction and inner rings are in an anti-clockwise direction.

Avoiding Parcel Linking failure

During Pre-Validation,when a new parcel is linked for the first time in Landonline to pass the Y004 pre-validation rule (or a parcel re-linked in Landonline to pass the Y015 pre-validation rule), Landonline will check for any mandatory or optional missed marks around the underlying parcels being extinguished in the survey. Any missed marks that bound the extents of the new subdivision can be included.

If you include any mandatory or optional missed marks that fall on the boundary of a donut parcel an application error message will appear and parcel linking will fail.

How do I deal with Donut Parcels?

In order to respect the topology of a donut parcel, you must address the inner ring parcels in the new survey.

If your survey is only dealing with the outer ring parcel, follow the steps below to ensure the topology of the inner ring is respected.

  • Turn on the ‘Underlying Marks’ layer and ensure you move this layer to the top of the ‘Current Layers’ tab.
  • Turn on the ‘Underlying Parcel Bdy Lines’ layer.
  • Turn on the ‘Underlying Vectors’ layer.

If there are no vectors in Landonline between all the existing nodes on the inner ring parcel, adopt the ‘Underlying Parcel Bdy Lines’ ensuring you adopt all of them.

If there are vectors captured between all the nodes on the inner ring parcel, then adopt those vectors.

If there are some boundaries with no vectors and some with, then you can adopt the vectors where there are some, and adopt the underlying parcel bdy lines for the rest.

You do NOT need to extinguish the inner ring parcel if you follow the above steps.

Failure to follow the above steps will result in mandatory/optional missed marks appearing on the inner ring boundaries – do no bring them in.  Instead, go through the above steps to ensure all the boundaries on the inner ring parcel boundaries are addressed.

If your survey is only dealing with the inner ring parcel, you do NOT need to address the outer ring parcel.

If you are creating a new donut parcel and both the inner and outer ring parcels are to be newly created parcels:

  • ensure that the inner ring parcel is linked BEFORE the outer ring parcel.
Last Updated: 13 July 2022