Profile: The Four-Person Firm Mapping the Waterfront

At seven in the morning the quay wall is still wet, and Dagny Ostrander is on her knees beside it with a steel pin and a tablet. Behind her, a drone the size of a loaf of bread rises with a sound like an angry fridge. Four people work for Ostrander & Pike Survey. Today three of them are here, and they will measure about two hundred metres of Halvering's waterfront to within a centimetre.

All figures below were given to this desk by the firm and are invented for this demonstration.

How it started

Ms Ostrander and Hugh Pike met on a council contract six years ago, each hired to survey the same stretch of road and each convinced the other's numbers were wrong. They were both right. It took a week to find out why: the council's reference marks had drifted.

They left to start their own practice with two second-hand instruments and HM 38,000 of savings. Their first client was a church that wanted to know whether its tower was leaning. It wasn't, but it was close, and the bill for telling them was HM 1,100.

What they sell

Not maps, they insist. Certainty. A developer, a harbour engineer or an insurer wants to know exactly where something is, and exactly how sure you can be. The firm's reports state the margin of error on page one in large type. "Nobody has ever complained about an honest number," Mr Pike says. "Only about a surprising one."

Revenue last year was HM 612,000, with a profit of HM 94,000. Its largest client, the Harbour Authority, accounts for just under a third of that, which both founders describe as "the edge of comfortable".

The drones

Two drones cut a survey from days to hours. They fly a fixed grid, photograph the ground from above and let software stitch the images into a model. The models are checked against a few hand-measured points per hectare. If the two disagree by more than two centimetres, the day is repeated.

The drones do not replace the tripod. They make the tripod's work go further.

The risk

Small firms like this one have a single point of failure, and it is the founders. Ms Ostrander admits that if she were hit by a bus the firm would last about four months. They are training a junior surveyor, Inez, and aiming to give her the lead on small jobs next spring.

Another risk is the Authority. A third of revenue from one buyer is a number any lender would circle. They've started bidding for private-estate work to loosen the dependency.

What it says about the city

Ostrander & Pike's work is dull in the best sense: it makes other work possible. If Halvering's quay walls are going to be rebuilt, someone has to know where they actually stand today. That someone is currently four people and two drones, and by seven-thirty the wall is dry.

Names, places and events in this demo are fictional.