When you link parcels spatially you must assess when to include missed marks in your survey. Missed marks are existing Landonline marks positioned on either external or internal boundaries you have not included in your survey. For example, where an abutting boundary intersects a boundary of your survey and you have not included dimensions to this position in your survey. Including these marks avoids creating gaps or overlaps in primary parcel topology (sliver parcels).
When missed marks are excluded, existing boundary lines are retained in Landonline and the new boundary line is also included. This may create gaps or overlaps in primary parcel topology (sliver parcels). Sliver parcels can be avoided by including them in your survey with boundary dimensions. This is more reliable and ensures your survey matches underlying data.
There are two types of missed marks:
- Mandatory - when there are three or more lines radiating from the mark
- Optional - when there are only two lines radiating from the mark. Where an Optional missed mark has a marked position (is official) it should be included in your survey, otherwise you should exclude it.
- Optional missed marks exist due to two reasons:
- official marks previously placed on a boundary as a line mark, or official marks located on an intersection and the intersection is removed by a newer survey.
- unofficial boundary positions created during the original capture of Landonline spatial data.
- When you link parcels you are prompted to include missed marks when they occur. You should only include these when you have captured all vectors in the survey.
- For surveys involving the capture of more than one parcel you can choose to include marks:
- after all parcels in the survey are defined. This is recommended.
- after defining each individual parcel in the survey. This is not recommended.
When you choose to complete the capture of all parcel vectors in your survey and then link, you should included missed marks when prompted. You will not have another opportunity to include missed marks unless you alter boundary vectors.
If you choose to link each parcel individually you are prompted to include missed marks every time you link. You should not include missed marks until you link the parcel that incorporates the final captured vector for the survey.
If you modify any boundary information after parcel linking, you must repeat the parcel linking and missed mark inclusion process.
Missed marks included in your survey are added to the Mark List screen as System Added marks.