Resources.

What this product is

1.1The LandSure 10-Year InSAR Land Subsidence Report (the Report) is an information product. It reports satellite-measured ground movement at discrete points on and near a property, and applies a fixed, rule-based screening classification (the Screening Classification) to those measurements.

1.2The Report is not geotechnical advice, engineering advice, a building report, a structural assessment, a land stability certificate, a hazard assessment, legal advice or financial advice, and it is not a substitute for any of them.

1.3The Report identifies where measured movement merits attention. It does not, and cannot, diagnose cause. Satellite radar measures that a surface moved. It cannot distinguish fill settlement from slope creep, from drainage failure, from foundation movement, from thermal behaviour of the structure itself. Establishing cause requires ground investigation by a suitably qualified professional, which for geotechnical questions in New Zealand means a Chartered Professional Engineer.

1.4A Screening Classification is a sorting outcome, not a finding of fact about a property, its buildings, its services, or its suitability for any purpose.

1.5LandSure does not visit the property, does not inspect any structure, and does not review any council record, geotechnical report, building consent or title document in producing the Report.

What is actually measured

2.1Measurements are derived from Copernicus Sentinel-1 C-band synthetic aperture radar, at a wavelength of approximately 5.55 cm, processed by SatSense Ltd into fitted displacement time series at persistent reflecting points.

2.2All movement is measured along the satellite’s line of sight, not vertically. The radar looks obliquely at the ground. What it records is the change in distance between the satellite and the reflector, projected onto that viewing direction. Movement is reported in millimetres per year along the line of sight (mm/yr LOS) unless the Report states otherwise.

2.3Combining the ascending pass, which looks approximately east, with the descending pass, which looks approximately west, allows movement to be separated into a vertical component and an east-west component.

2.4North-south movement is poorly observed. Because both viewing geometries look east or west, ground moving purely north or south changes the satellite-to-ground distance very little, and can register at or near zero in both geometries. This is a property of every InSAR product in existence, whether or not the provider states it. Where the dominant movement at a site is north-south, the Report will under-report it, and may report the site as stable.

2.5Measurements are relative, not absolute. Every displacement value is measured with respect to a processing reference, and describes movement of a point relative to that reference and to the surrounding network. The Report is designed to be read as a comparison between a property’s points and their immediate surroundings. It is not a survey, it does not establish an absolute height or level, and it must not be used as one.

2.6Where the Report presents a vertical rate, that value rests on an assumption about the direction of movement. Where the true movement is not vertical, the stated vertical rate will be wrong in magnitude, and the error is not detectable from the data alone.

Where points form, and where they do not

3.1A Monitoring Point exists only where the ground returns a stable radar echo pass after pass. In practice this means hard, dry, geometrically stable surfaces: roofs, driveways, paving, concrete, kerbs, retaining walls and exposed rock.

3.2Vegetated ground yields no reliable measurement. Grass, gardens, crops, scrub and bush canopy rearrange between passes at the scale of the radar wavelength, returning an incoherent echo. Lawns, paddocks and bush-covered land will carry few Monitoring Points or none at all, and parts of a property may therefore be entirely unmeasured.

3.3Water surfaces yield no measurement. Sand, loose gravel, freshly worked earth and snow-covered ground yield no reliable measurement.

3.4Steep slopes may carry reduced or no coverage. Side-looking radar compresses slopes facing toward the sensor and is blind to slopes steep enough to fall in radar shadow. Some hillside properties, including some of those where slope stability is the reason a customer sought a Report, will return fewer usable points than flat ground nearby. Absence of points on a slope is not evidence that the slope is stable.

3.5A Monitoring Point measures its own reflector, and nothing else. A stable driveway point states that the driveway is stable. It does not certify the lawn beside it, the ground beneath it, the dwelling next to it, or any subsurface condition.

Points, not parcels

4.1The Report describes measured reflectors. Ground between Monitoring Points is not measured. The Report does not interpolate across unmeasured ground, and any inference drawn about ground between points is the reader’s judgement, not a measurement.

4.2The radar resolution cell covers an area of ground several metres across. A single Monitoring Point represents the aggregate behaviour of everything within that cell that reflects, not a single surveyed spot.

4.3The mapped position of a Monitoring Point carries positional uncertainty of the order of several metres. Where structures, boundaries or features sit close together, a point plotted inside a boundary may correspond to a reflector just outside it, and the reverse. Point positions on the Report map are indicative. They must not be used to attribute movement to a specific structure, a specific boundary, or a specific party, and they must not be used in any boundary, easement or liability dispute.

4.4The 90 metre query radius is applied to the property boundary supplied by Toitū Te Whenua LINZ. Where that boundary is itself imprecise, or where a title has changed since the boundary data was published, the set of points returned will reflect the boundary data rather than the legal boundary.

Time, and the limits of the record

5.1The Assessment Period is the exact date range stated on the face of the Report. Every rate, total and classification in the Report describes that period and no other.

5.2The New Zealand archive begins in 2014. No Report can describe ground movement before that date, whatever the property’s history.

5.3A Monitoring Point’s record begins when its reflector appears and ends when it changes. Re-roofing, cladding, extension, resurfacing, new construction and major landscaping replace the reflector being measured. The record shortens, restarts, or ends. A dwelling built in 2023 has no ten-year history, and cannot be given one.

5.4Acquisition frequency is set by the Copernicus programme and its published observation plan, not by LandSure. The revisit interval over New Zealand may change during the life of a Report as the Sentinel-1 constellation is reconfigured. Any interval stated in the Report or in LandSure documentation describes the plan current at the date of issue and is not a commitment to a future acquisition frequency.

5.5LandSure has no obligation to update, re-check, re-issue or monitor a Report after delivery, and no obligation to notify any person of anything measured after the Assessment Period ends.

5.6Data supply may be interrupted, degraded, restricted or discontinued by the European Commission, the European Space Agency, SatSense or Earth Sciences New Zealand at any time. LandSure is not liable for the consequences of any such interruption.

How fast movement can be, before it is missed

6.1There is an upper limit to the rate of movement this method can measure, and above it the method does not merely fail: it can return a wrong answer that looks like a right one.

6.2Radar phase repeats every half wavelength of range change, approximately 2.8 cm along the line of sight. Where the ground moves more than that between two acquisitions, or where movement varies sharply over a short distance, the processing cannot always determine how many whole cycles have elapsed. The result may be an under-stated rate, a rate of the wrong sign, or the loss of the point altogether.

6.3A consequence follows that every reader must understand: rapid ground movement, of the kind associated with an active landslide, a slip, a sinkhole or a sudden failure, may be reported as slow movement, as no movement, or as no measurable points at all. This method is designed to detect slow, steady movement over years. It is not a landslide warning system, it is not an early-warning system of any kind, and it must never be relied on as one.

6.4Movement that is rapid and localised is the case the method handles worst, and it is also the case with the greatest consequence. Where there is visible evidence of instability at a property, including cracking, tilting, distortion, ground fissures, disturbed drainage or recent slippage, that evidence takes precedence over anything in the Report, and a Chartered Professional Engineer should be engaged regardless of the Screening Classification.

Sources of error in the measurement

7.1Atmosphere. Water vapour, pressure and temperature vary between acquisitions and delay the radar signal. On any single acquisition this can resemble several millimetres of movement. Processing across a long stack reduces it toward zero because it is largely random, but it is never entirely removed, and it is not random where it correlates with topography.

7.2Terrain model error. Removing the topographic contribution to phase relies on a digital elevation model. Error in that model leaves a residual signal in the result, which is largest where terrain is steep or the model is coarse.

7.3Thermal movement of structures. Buildings, bridges, retaining walls and paved surfaces expand and contract with temperature. A reflector on a structure records the structure’s own thermal cycle in addition to any ground movement. This appears in the record as a seasonal signal and is not, by itself, evidence of ground movement.

7.4Seasonal ground behaviour. Expansive clays swell and shrink with soil moisture, producing a regular annual cycle. Soil moisture, groundwater level and rainfall all move the ground surface reversibly. A seasonal cycle is normal behaviour, not a defect, and the Screening Classification reads the multi-year trend through it rather than the cycle itself.

7.5Single measurements. A single 12-day measurement of a point carries several millimetres of scatter. No classification, alert or conclusion is ever drawn from a single acquisition. A single pass largely measures the weather.

7.6Fitted velocities. A fitted long-record velocity resolves to approximately one millimetre per year in good conditions: a stable reflector, a long unbroken record, and a dense surrounding network. That figure is a best case. Precision at any individual point depends on the number of observations, the stability of the reflector, and local conditions, and the Report states the confidence grade that applies.

7.7Every rate in the Report is an estimate with an uncertainty, not an exact quantity. A rate close to a classification threshold may sit on either side of it once uncertainty is accounted for, and a small change in rate between one Report and the next may reflect measurement uncertainty rather than a change in the ground.

How the classification works, and what it does not mean

8.1The Screening Classification is rule-based. The same measurements and the same thresholds always produce the same result. It involves no judgement, no interpretation and no discretion, and it is not moderated by any person.

8.2A property’s headline classification is the classification of its single worst-performing point. Screening is designed to surface the point most deserving of attention rather than average it away. Every other point is reported individually.

8.3Stable does not mean safe. A Stable classification states that measured points moved within the stable band during the Assessment Period. It says nothing about unmeasured ground, unmeasured directions of movement, movement too rapid to measure, subsurface conditions, contamination, flooding, the condition of any structure, or future behaviour.

8.4Investigate does not mean damaged. An Investigate classification states that at least one point met or exceeded the professional-review threshold. It is a prompt to obtain a site-specific geotechnical review. It is not a finding of damage, defect, fault, negligence or liability on the part of any person, and it must not be represented as one.

8.5Zone boundaries shown in LandSure figures are illustrative. The exact thresholds applied are those stated in the Report methodology current at the date of issue, and they may be revised.

8.6A Report is not a valuation input, an insurance determination, a lending decision, a building consent document, a due diligence substitute, or evidence in any proceeding about the condition of land or buildings. Any person choosing to use it for such a purpose does so on their own assessment and at their own risk.

Pre-purchase acknowledgement

9.1Before payment is taken, every Customer is shown a sequence of short statements setting out the principal limitations of the Report, and must positively acknowledge each one. The order cannot proceed until every statement has been acknowledged. Those statements mirror the ten points published above.

9.2The statements summarise clauses 1 to 8. They do not replace these terms, and these terms apply in full.

9.3By completing that sequence the Customer acknowledges that the limitations were disclosed before purchase, that the free Limitations and appropriate use document was available to read without purchase, and that the Customer entered the contract on that basis.

9.4LandSure records for each order: the statements shown, their version identifier and content hash, the time and date each was acknowledged, and the order to which they relate. An electronic record of this kind satisfies the requirements for information in electronic form under Part 4 of the Contract and Commercial Law Act 2017. CCLA 2017 Pt 4 The record is retained per clause 12.4 and is available to the Customer on request.

9.5The acknowledgement statements are repeated in the order confirmation email, so the Customer independently holds a copy of what they were shown.

9.6Nothing in the acknowledgement sequence limits any right the Customer has under clause 10, and no acknowledgement operates as a contracting out of the Consumer Guarantees Act 1993 in a consumer transaction. CGA 1993 s 43(1)

Your rights as a consumer

10.1Nothing in these terms limits or excludes any right or remedy you have under the Consumer Guarantees Act 1993 or the Fair Trading Act 1986 where those Acts apply and cannot lawfully be excluded. CGA 1993 s 43(1) FTA 1986 s 5D

10.2Where a Report is supplied to a Customer who is a consumer within the meaning of section 2 of the Consumer Guarantees Act 1993, the guarantees in sections 28 to 32 of that Act apply: that the service will be carried out with reasonable care and skill, will be reasonably fit for any particular purpose made known to LandSure, will be completed within a reasonable time, and will be supplied at a reasonable price where none is agreed. CGA 1993 ss 2, 28–32

10.3Where a Report is supplied and acquired in trade, all parties are in trade, and the parties agree in writing to contract out, the Consumer Guarantees Act 1993 is contracted out of to the extent permitted by section 43(2) of that Act, and Part 1 of the Fair Trading Act 1986 is contracted out of to the extent permitted by section 5D of that Act. CGA 1993 s 43(2) FTA 1986 s 5D

10.4In assessing whether it is fair and reasonable for the parties to be bound by a contracting-out provision, a court has regard to the subject matter of the agreement, the value of the goods or services, the parties’ respective bargaining power, and whether any party received legal advice. CGA 1993 s 43(3) The parties record that: the limitations of the product are published in full and free of charge before purchase; the price is modest relative to the decisions the Report informs; and any party acquiring in trade is expected to have the capacity to obtain advice.

10.5A supplier who purports to contract out of the Consumer Guarantees Act 1993 other than as permitted commits an offence under section 13(i) of the Fair Trading Act 1986. CGA 1993 s 43(4) FTA 1986 s 13 LandSure does not assert any contracting out against a consumer, and any clause read as doing so is to be read down to the extent necessary.

10.6Nothing in these terms permits misleading or deceptive conduct. LandSure must not engage in conduct that is misleading or deceptive or likely to mislead or deceive, must not make false or misleading representations about its services, and must have reasonable grounds for any representation at the time it is made. FTA 1986 ss 9, 11, 12A, 13 No disclaimer in these terms excuses conduct that would breach those provisions, and a disclaimer does not cure an overall impression that misleads.

10.7Every accuracy figure LandSure publishes, including any statement of precision in millimetres per year, is a representation for the purposes of section 12A of the Fair Trading Act 1986 and is supported by the published technical specification and by the processing partner’s stated performance. FTA 1986 s 12A

10.8Where these terms are a standard form consumer contract, or a standard form small trade contract, a court may declare a term unfair, and an unfair term cannot be relied on. FTA 1986 s 26A, ss 46H–46M LandSure’s intention is that every term here is reasonably necessary to protect its legitimate interests given the nature of the product, and any term found unfair is severable under clause 15.8 without affecting the rest.

Reliance, and who a Report is for

11.1A Report is issued to the Customer who commissioned it, for that Customer’s own use, in relation to the property identified on its face. No other person may rely on it.

11.2LandSure owes no duty of care and accepts no liability to any person who is not the commissioning Customer, including without limitation any purchaser, vendor, tenant, lender, insurer, broker, valuer, real estate agent, solicitor, engineer, territorial authority or subsequent owner who is shown, sent or given a copy, whether by the Customer or by anyone else.

11.3A Report is accurate only when read in full. Extracts, single pages, screenshots, tables lifted out of context and figures quoted apart from the limitations that qualify them are not authorised, must not be circulated, and must not be relied on. Share a Report complete and unaltered, or not at all.

11.4A Report may not be used in marketing material, a property listing, an advertisement or a sale document without LandSure’s prior written consent. A vendor or agent who presents a Report, or any part of it, in a way that creates a misleading impression about a property may breach sections 9, 11 and 13 of the Fair Trading Act 1986 in their own right, and section 14 in relation to land. FTA 1986 ss 9, 11, 13, 14 That is their exposure, not LandSure’s, and this clause is notice of it.

11.5Where a Customer supplies a Report to a professional adviser, the Customer must make clear that LandSure offers that adviser no reliance. The adviser’s own duty to the Customer is unaffected by anything in these terms.

11.6A Report speaks as at its issue date. A Report older than 12 months should be re-run before it informs any decision.

11.7Nothing in this group limits any liability that cannot lawfully be limited, including liability for fraud.

Privacy

12.1LandSure collects, holds, uses and discloses personal information in accordance with the Privacy Act 2020 and the information privacy principles it sets out. Privacy Act 2020

12.2Collected: the property address to be assessed, the Customer’s name and contact details, order and payment records, and the acknowledgement record in clause 9.4. Purpose: to identify the property, produce and deliver the Report, take payment, provide support, and meet legal and accounting obligations. The purpose is stated at the point of collection as principle 3 requires. IPP 1, IPP 3

12.3Disclosure outside New Zealand. Property coordinates are provided to SatSense Ltd in the United Kingdom to run the data query. Before disclosing personal information to a foreign person or entity, LandSure satisfies itself that the recipient is subject to safeguards comparable to those in the Privacy Act 2020, as principle 12 requires. IPP 11, IPP 12 Payment details are handled by the payment provider and are not stored by LandSure.

12.4Retention. Reports remain accessible for 7 years. Order, payment and acknowledgement records are retained for 7 years for accounting, tax and evidential purposes. Personal information is not kept for longer than is required for the purposes for which it may lawfully be used. IPP 9

12.5Access and correction. You may request access to, and correction of, personal information LandSure holds about you. IPP 6, IPP 7 Contact [email protected]. LandSure responds within the statutory timeframe.

12.6Complaints. You may complain to LandSure at [email protected], and to the Office of the Privacy Commissioner at privacy.org.nz. Privacy Act 2020, Pt 5

12.7Where LandSure collects personal information about a person from a source other than that person, the notification obligations in principle 3A apply. IPP 3A, in force 1 May 2026

12.8A Report concerns a parcel of land. Where a property address is also a person’s home address, LandSure treats the order record as personal information and handles it accordingly.

Limitation of liability

13.1This group is subject to clause 10 in its entirety, and does not apply to the extent that it would limit a right or remedy that cannot lawfully be limited.

13.2To the fullest extent permitted by law, LandSure’s total aggregate liability arising out of or in connection with a Report, whether in contract, tort including negligence, equity, under statute or otherwise, is limited to the amount paid for that Report.

13.3LandSure is not liable for indirect or consequential loss, or for loss of profit, loss of opportunity, loss of expected savings, diminution in property value, remediation or geotechnical investigation costs, costs of delay, or loss arising from a decision to buy, sell, insure, lend against, develop, subdivide or decline any property.

13.4Without limiting clause 13.2, LandSure is not liable for loss arising from movement the method could not observe, including movement on surfaces yielding no Monitoring Points, movement between points, north-south movement, movement too rapid to resolve as described in group 6, movement outside the Assessment Period, or subsurface conditions of any kind.

13.5LandSure is not liable for any error, omission, change, interruption or withdrawal in data supplied by the European Space Agency, the European Commission, SatSense Ltd, Earth Sciences New Zealand, Toitū Te Whenua LINZ, Manaaki Whenua Landcare Research or any other third-party provider.

13.6Refunds follow failure of the product, not its findings. A Report containing a data error, or covering the wrong property through LandSure’s error, is refunded. An unwelcome classification is not a defect: the Report is the measurement, whatever it shows. Where the Consumer Guarantees Act 1993 applies, the Customer’s remedies under that Act are in addition to this and are not displaced by it. CGA 1993 s 32

13.7Each limitation operates separately. If any is held unenforceable or is declared unfair, the remainder continue to apply.

13.8LandSure does not exclude liability for fraud, for fraudulent misrepresentation, or for any liability that cannot lawfully be excluded.

Limitation periods, complaints and disputes

14.1Raise any issue with [email protected], quoting the report ID printed on every page. LandSure will acknowledge within 2 working days and will state what it will do and by when.

14.2LandSure will tell any Customer with an unresolved complaint about the options open to them, including those below. It will not require a Customer to waive any of them as a condition of considering a complaint.

14.3Disputes Tribunal. A Customer may bring a claim in the Disputes Tribunal for claims up to $30,000. No lawyer is required and the filing fee is modest. Disputes Tribunal Act 1988

14.4Commerce Commission. A person who believes LandSure has engaged in misleading conduct may complain to the Commerce Commission. A contracting-out provision does not prevent the Commission acting. FTA 1986

14.5Privacy Commissioner. Privacy complaints may be made to the Office of the Privacy Commissioner. Privacy Act 2020, Pt 5

14.6Before commencing proceedings the parties will attempt in good faith to resolve the matter by discussion, and may agree to mediation. This does not prevent either party seeking urgent interim relief, and does not extend any limitation period.

14.7Limitation periods. A money claim must generally be filed within 6 years of the act or omission. A late knowledge extension of up to 3 years from the date the claimant knew or ought reasonably to have known the relevant facts may apply, subject to a longstop of 15 years. Limitation Act 2010 Nothing in these terms shortens a statutory limitation period.

14.8Claims relating to building work are additionally subject to the 10-year longstop in section 393 of the Building Act 2004. A Report is not building work and is not a producer statement, and this clause is included because Customers frequently ask which period applies to a property matter. Building Act 2004 s 393

Data sources, intellectual property, website and governing law

15.1Every Report is built from third-party data supplied under the licences below. These attributions are required by those licences and are reproduced in the form they specify. They must not be reworded.

Satellite radar. Contains modified Copernicus Sentinel data. The Copernicus Sentinel data licence supplies that data without any express or implied warranty, including as regards quality and suitability for any purpose, and requires users to renounce claims for damages against the European Union and the data providers.

Property boundaries. Contains data sourced from the LINZ Data Service licensed for reuse under CC BY 4.0.

InSAR processing. Displacement measurements are processed by SatSense Ltd, a University of Leeds spin-out, using its own methods.

National dataset. The New Zealand national ground-movement dataset is produced by SatSense in partnership with Earth Sciences New Zealand, formerly GNS Science.

Land and soil context. Land and soil classifications are sourced from Manaaki Whenua Landcare Research and Toitū Te Whenua LINZ.

15.2These clauses are the operative summary of the full instruments at /legal/terms, /legal/privacy and /legal/attribution. Where this summary and a full instrument differ, the full instrument governs.

15.3Intellectual property. Report layout, written content, classification methodology, figures and this website are protected under the Copyright Act 1994 and belong to LandSure and AVANT Global. Copyright Act 1994 Underlying measured data remains the property of its providers.

15.4You may not resell a Report, incorporate it into a product or service offered to others, use it to train or evaluate any automated system, extract data from it in bulk, or remove or alter any attribution, notice or identifier it carries.

15.5This website. The website and its documents are provided for general information, are current at the revision date shown on each, and may be superseded without notice. LandSure does not warrant uninterrupted or error-free availability. Downloading a document does not create a customer relationship and does not entitle any person to rely on it in relation to a specific property.

15.6Governing law. These terms are governed by New Zealand law and the New Zealand courts have exclusive jurisdiction.

15.7Changes. These terms may change. The version applying to a Report is the version published when that Report was ordered, identified by the revision code and effective date at the head of this section. Superseded versions are retained and available on request.

15.8Severability. If any provision is held unenforceable, invalid or unfair, it is severed to the minimum extent necessary and the remaining provisions continue in force.