Measure/Measure vs a site walk vs a survey
Comparison
Measure vs walking the site vs a land survey
Three instruments, three different questions. A site walk sees condition. A licensed survey establishes elevation and boundary to a legal standard. A remote terrain measurement computes where water goes, at scale, without travel. None of them substitutes for the other two, and this page is about where each one stops.
We sell the third. So the fair test of this page is whether it is useful when it says our own instrument is the wrong tool, and it says that several times below.
The comparison, directly
| Question | Site walk | Licensed survey | Measure |
|---|---|---|---|
| Slope at one wall | Yes, with a string line | Yes, to a legal standard | Yes, with a range from 17 footprint positions |
| Slope at every wall of every building | Time-limited | Costly at scale | Yes, uniformly |
| Upstream contributing area per wall | Largely invisible from the ground | Only if the survey extends far enough | Yes, in m², with a range |
| Where surface flow concentrates | Only during rain | Inferable from contours | Yes, modeled and accumulated |
| Closed depressions and their depth | Only when full | Yes, from contours | Yes, filled to the spill point |
| Soil, infiltration, water table | Partly, by eye and by auger | No — that is geotechnical | No |
| Downpipe discharge and hard surfaces | Yes | Located, not diagnosed | No |
| Anything subsurface — drains, pumps, pipe runs | Partly, by inspection | Sometimes located | No |
| Condition inside the building | Yes | No | No |
| Boundaries, easements, legal elevations | No | Yes — the only one | No |
| Risk of measuring the wrong building | Effectively none | None | Real, and quantified |
| Cost and speed on one property | A visit | Highest, slowest | $25, minutes |
| Cost and speed on five hundred | Impractical | Impractical | Practical |
Where the site walk wins, and it is not close
Everything that is condition rather than geometry. Staining, efflorescence, cracking, a settled backfill trench, a downpipe discharging at the wall, a patio pitched the wrong way, what the soil does when you dig it, and the entire interior. A terrain model observes none of this.
The site walk also has no identity failure mode. The person is standing in the driveway. That sounds trivial and it is the single biggest structural advantage a visit has over any remote method — including ours.
Where the licensed survey wins
Anything with legal weight. Boundaries, easements, elevations that go on a plat or into a permit, and any situation heading toward a dispute. A survey is also the higher-fidelity elevation measurement on the parcel itself, because it is made on the ground with instruments rather than from an aircraft.
Measure is explicitly not a survey and not an engineering analysis. Where a number needs to be defensible in front of a municipality or a court, this is the wrong instrument and we will say so on the call.
Where the remote measurement wins
Contributing area
The thing you genuinely cannot get from the yard. Most of the land draining to a wall is not in view from beside that wall, and a good portion of it is usually off the property. Two walls at an identical −6% can be different jobs by an order of magnitude — one collecting a side yard, the other collecting the back half of a hillside.
Uniformity
Every wall of every building gets the same treatment: slope measured 0.75 m to 3.25 m out on that wall's own outward normal, repeated and combined the same way every time, against a 5% fall over 3 m target. Not the two elevations somebody had time for before the next appointment.
Scale
Five hundred properties measured the same way, ranked against each other. Neither of the other two instruments does this at any price anybody pays.
An explicit account of what it refused
The ground surface is gated before anything is computed — the median step between adjacent elevations must clear 0.004 m, below which the surface is a coarse source stretched onto a fine grid and every channel drawn from it is interpolation presented as measurement. Failing addresses are refused with the measured step attached rather than quietly downgraded.
The remote method's own failure mode, quantified
Two of them, and both are published rather than buried.
1. Which building the address names
Identity is decided by graded evidence, strongest first, with the nearest outline alone treated as a guess rather than an identification. The grade that answered ships with the result, so an identification and a location are never mistaken for each other, and where nothing identifies a structure the address is refused rather than matched to the nearest roof.
Where the underlying records are thin, the evidence is thin too — rural addresses, new construction and recently renumbered streets are the hard cases. And not every disagreement is a different building: some are our outline and somebody else's tracing the same roof and disagreeing about where its center sits.
A person standing in the driveway has none of this problem. That is the honest score.
2. The footprint is a trace, not the wall
A published outline can sit a meter from the wall it claims to be. On a real Pittsburgh footprint, shifting it north in 0.2 m steps moved one wall from +5.4% to −23.5%, crossing zero inside 1.4 m.
The response is to displace the footprint one meter in each of sixteen directions and re-measure — seventeen positions — and publish a direction only when all seventeen agree on the sign. Everything else ships as too close to call, with which way it leans and how many of the seventeen agreed.
What none of the three establishes
That a particular property has a drainage problem, a wet basement, or any defect in the future. A site walk sees what has happened; a survey sees geometry; a terrain model sees the ground. Ground falling toward a foundation raises the risk of water reaching it — ordinary building science. A prediction about one building is a different claim and none of these three instruments makes it.
We also quote no conversion rate for contractor outreach. Measured terrain against Chicago's 311 basement-water complaints did not separate them — largely a verdict on the proxy, entirely a reason not to promise a number we have not observed.
The sensible sequence
- Measure first, because it is $25 and minutes, and it tells you which walls and how much upstream land — the two things that size everything downstream.
- Walk the site second, with the measurement in hand, and spend the visit on condition rather than on rediscovering the geometry.
- Commission a survey when a number has to be legally defensible, or when the work crosses a boundary, an easement or a permit.
Reverse that order and you pay the most expensive instrument to answer the cheapest question.
Try it on a property you already know well
The only calibration that means anything: run an address you have already walked or already dug at, and see whether the walls we call match what you found. A free lookup identifies the building and shows the shape of what was measured; the full report with every wall as a number is $25.
Contractors: territory access starts at $14 per property. Portfolios and books: talk to us.
Can it replace a site visit?
No, and it is not sold as one. It replaces the part of the visit that was geometry, and it adds contributing area, which the visit could not get.
Can it replace a licensed land survey?
No. Boundaries, easements and legally defensible elevations require a licensed surveyor. Measure produces computed estimates and is explicitly not a survey.
What can it see that a person in the yard cannot?
Contributing area, closed depressions with no outlet, and a uniform slope method applied to every wall rather than the two somebody had time for.
How do you know the address matched the right building?
Identity is settled by graded evidence, strongest first, the result says which grade answered, and where none is strong enough the address is refused rather than matched to the nearest roof. A site visit has no equivalent failure mode.