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Risk-based acceptance framework for Cadastral Survey Datasets (CSDs)

Background

LINZ developed and implemented a new risk-based acceptance framework in 2008.

This framework underpins a cadastral survey validation process that supports a wider initiative based on a first time compliance model that aligns with our goals of Optimal Regulation – 'As little as possible, as much as necessary' and e-Delivery excellence.

Current assurance environment

The survey system as a whole functions within a regulatory controlled environment that provides assurance of compliance at several levels. Within the end-to-end process, there is duplication of compliance effort by both surveyors and LINZ in assessing the quality of every cadastral survey dataset (CSD) and determining compliance before integration into the cadastre. Therefore, given this duplication, past levels of LINZ validation effort have not accurately and appropriately reflected the risks associated with each lodged dataset. Nor has the validation process always consistently reflected the gains and advantages available from a world class automated e-survey processing system, especially with 100% e-lodgement.

Objective of the framework

The objective is for LINZ to achieve consistency, effectiveness and greater efficiency by better utilising the automated Landonline tools when processing CSDs. The new process will make better use of resources by aligning LINZ's validation analysis to the risk profile of each dataset.

Risk-based acceptance framework

The framework is based on an assessment matrix comprising two primary elements – the surveyor's profile and the dataset's complexity. Together, these two profiles define the dataset risk profile.

The desired LINZ validation effort, to apply to each dataset being processed, is codified against this dataset risk profile. The following diagram and profile descriptions summarise the framework.

  Dataset Complexity Profile
  Low Med High
1 Low Risk
CSD Profile
Low Risk
CSD Profile
Medium Risk
CSD Profile
2 Low Risk
CSD Profile
Medium Risk
CSD Profile
High Risk
CSD Profile
3 Medium Risk
CSD Profile
High Risk
CSD Profile
High Risk
CSD Profile
Surveyor Profile
The Surveyor Profile provides an objective assessment of the likelihood that the surveyor's CSD will be first time compliant. This is a LINZ measure based on an historical analysis of the surveyor's previous performance including requisitions and reviews. Surveyor Profiles will be regularly reviewed.
Dataset Complexity Profile
The Dataset Complexity Profile indicates the surveyor's assessment of the risks attributed to their CSD. It reflects the level of manual analysis, in addition to the automated business rule reports, that is required to provide confidence to the surveyor that their dataset complies with the Surveyor-General rules and specific statutory requirements.

Parameters used in calculating the Surveyor Profile

The following parameters were included in the requisition analysis:
  • Number of CSDs submitted: <10, >24, other
  • Number of both significant and critical requisitions per CSD: >1, <0.15, other
  • Number of critical requisitions per CSD: >0.04, = 0, other
The requisition analysis together with results for recent audits and reviews, provided the surveyor profiles in the range 1 - 3 with 1 indicating the most likelihood of first time compliance.

Criteria to be used in calculating the Dataset Complexity Profile

The following is the current criteria to guide surveyors in determining the complexity profile of each dataset lodged.

Profile Dataset Complexity Criteria – to determine Dataset Complexity Profile
Low Parent parcels are defined by survey that have previously been captured into Landonline
> 50% marks have SDC status (approximate)
No conflicts with underlying data
Compiled and Computed surveys (unless subject to SG Approval)
Record Purposes
Survey Information
Flats/Cross Lease
Medium < 50% marks have SDC status (approximate)
Complex easements
Standard unit developments
High Parent parcel boundaries being redefined as different from current cadastral record
Staged Unit Developments
Unit Re-Developments
Strata
Complex natural boundary (not adopted); accretion/erosion and MHWS/MHWM
Land being brought under the Land Transfer Act
Multiple Pt lots with same lot number
Titles limited as to parcels or interim titles
Parent parcel includes Diagrams on Transfer
Other conflicts in the cadastre
Unexplained discrepancies between survey definition and occupation
Known areas of ground movement (eg Edgecumbe and Moeraki, Bisley Av Nelson)
Very old surveys (pre 1930) supporting guaranteed titles – where the record is poor
Datasets that require the statutory approval of the Surveyor-General, in addition to the LINZ Chief Executive’s determination of compliance

Quality assurance of the new framework and validation process

LINZ will analyse a percentage of validated datasets to ensure the new acceptance process is robust and the surveyor and dataset complexity profiles are correct. The results of this analysis will also provide an opportunity for LINZ to routinely assess and refine the framework and validation process.