Pre-validating e-surveys

 

Landonline pre-validation is available for use at any time to assess the quality and compliance of an e-survey.

Pre-validation tests an e-survey in two ways:

  • It provides an internal integrity assessment on the e-survey, and
  • It identifies potential inconsistencies between the e-survey and Landonline data.

Pre-validation uses the same automated business rules that LINZ staff use when an e-survey is being processed for approval, ensuring users have control of quality.

The results of the pre-validation are listed in a report.  The report outlines the rules that have identified potential issues and their level of severity, along with the rules that have run without identifying conflict.

Where issues are identified, they should be addressed before lodgement to ensure streamlined processing and prompt approval.

You can find step-by-step instructions on the pre-validation process here.

Pre-validation by batch process

You can also pre-validate by batch process. This section describes that process.

Explanation of the e-survey Pre-validation Report and Accuracy Rule Tests run during pre-validation of CSDs

To assist surveyors, LINZ has prepared a summarised explanation of the items in the pre-validation report - (pdf 674KB) to assist interpretation.

For information about the accuracy-related business rule tests that are run as part of the CSD pre-validation process, see Accuracy Rule Tests run during Pre-validation of CSDs - (pdf 782KB).

Additional information about pre-validation reports can be found in the Tips & Hints section.

e-survey Pre-validation Report - A QA Tool?

e-survey users occasionally ask: Why is the pre-validation report so long?  What use is all the information to me?  What should I be doing with this information?  On occasions, users may have been incorrectly advised to just look out for the Fatal Y rule failures or C Rule Conflict Messages and ignore the rest.  This advice is quite incorrect.

Pre-validate allows e-survey users to validate their survey against a set of pre defined automatic business rules and manual business rules that apply to the Survey Purpose they have selected.

So that users do not need to review multiple reports to determine the status of the pre-validation, a single text based pre-validation report is generated that contains the results of the automated business rules, the topology validation report (if applicable) and the adjustment validation reports (if applicable).  The pre-validation report also includes, for the users reference, a list of the manual rules that LINZ may apply to the dataset during formal validation.

The pre-validation report provides a Quality Assessment tool that can greatly assist the user examine his/her own dataset in preparation for Submit and approval. The report details potential inconsistencies in the survey which can then be corrected. It reports conflict with Landonline which can be assessed for validity and corrected if need be. LINZ recommend that the entire report is reviewed and that appropriate items are actioned before a survey is committed to Submit.
Obviously the amount of information included in the pre-validation report can be substantial. To make it easier for users to interpret the results, the pre-validation report conforms to the following structure:

  • Non compliant results from automated rules ordered by severity.
  • Compliant results from automated rules.
  • Topology Report (if applicable).
  • Adjustment reports (if applicable).
  • Manual validations that may be formally assessed.

The Y Rules

These are the Cadastral Survey Integrity rules.  Any Y rule failures must be corrected before submission of the dataset can proceed.

Note:

  • If Y rules 014, 021, 023 or 024 fail, Landonline will still validate the e-survey against the Cadastral e-survey business rules (C rules) as long as all other Y rules are compliant.
  • If Y rule 021 fails, but C rules run, then the Plan Layout validation rules (P rules) will not run.

The C Rules

  • C Rule 'Conflict' Messages must be actioned for the data to meet the criteria for approval as to survey.
  • Submit may succeed, but failure to address the Conflict C Rules will incur requisitions when the survey is processed by LINZ.
  • C Rule 'Warning' Messages may or may not require action. They report possible issues that may not actually be errors but require your consideration. They may highlight discrepancies that need clarification in the survey report.

The P Rules

  • These are the plan layout rules.
  • As with other e-survey rules, any plan layout rules configured for the survey transaction type that are considered significant or fatal will be automatically run as part of the submit process.
  • A non compliant result for one of these rules will only prevent submission of the survey if the rule is fatal.

Manual Rules

  • This is a list of the manual rules that LINZ may apply to the dataset during formal validation.
  • They are provided for the user's reference only.
  • No action is required but the rules will assist with Quality Assessment.

The Adjustment Reports

Internal Consistency Report

The adjustment tests the internal consistency of all survey observations and boundaries supplied with the survey dataset (including any adopted boundaries or observations).  This is equivalent to testing traverse and parcel closes.

It also tests whether the observations meet the requirements of Regulation 28 of the Surveyor-General's Rules for Cadastral Survey 2002/2, and whether the relative accuracy of nodes meets the requirements of Regulation 26.

It verifies that witness marks from the survey meet the requirements of Regulation 13.

The Network Adjustment (Partial SDC) Report

In this test, the underlying nodes that have SDC coordinates are held fixed.  The compatibility of the new survey data and the SDC coordinates is then tested. A failure in this adjustment indicates a need to re evaluate the underlying survey data and coordinates, particularly if the new dataset has passed the internal consistency adjustment.  A pass in this adjustment will mean that the resulting coordinates have the potential to become SDC.

The SEUW is only a guide to the strength of the survey network.  It needs to be considered in relation to the complexity of the dataset and the accuracy of the underlying Landonline data. A value of <1 is an indication of a strong survey.  Users should check whether or not any vectors fail any of the Surveyor-General's Rules tests.