Coverage · St. Thomas
Construction survey on St. Thomas.
Steep benched lots, a historic core with party walls on every side, and a working harbour — three different survey problems inside thirty-two square miles. We are based at Red Hook, which means the aerial and scanning work reaches any of them the same day.
Terrain and constraints
One island, four survey problems.
St. Thomas does not have a typical site. It has a handful of distinct ones, and they want different things from a survey crew.
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Hillside development and benched lots
The island is a ridge with the sea on both sides, so most of what gets built is cut into a slope. A benched lot changes twice: once when it is cut and again when the retaining goes in. Both states are worth a surface, because the quantity argument later is almost always about how much came out of the hill.
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Retaining structures
Walls are not incidental here; they are frequently the largest single element of the earthwork. Capturing the face before backfill, and again as built, gives you a dimensioned record of a structure that becomes invisible the moment it is buried.
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The Charlotte Amalie core
Dense, old, and built to the boundary. Party walls, shared drainage, and stone construction altered repeatedly across a century with no drawing set surviving. Sky view between buildings is poor enough that GNSS degrades, so control comes off the total station.
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Harbour and marine infrastructure
Bulkheads, docks, and revetments where the useful measurement is the interface between water and structure. Waterfront capture is also weather-bound in a way inland work is not, so the schedule carries more contingency.
Cruise and port facilities are their own category again. The survey work is ordinary; the access is not. Those facilities set their own clearance and their own operating restrictions, and that is a scoping conversation rather than something to discover on the morning of the capture. What we can put in front of a facility is set out on the capabilities page: Part 107, NDAA-compliant aircraft, and a licensed surveyor of record.
Airspace
Cyril E. King sits in
the middle of the work.
On a lot of islands airspace is a footnote. On St. Thomas the Class D surface area around Cyril E. King covers a meaningful share of the developed south and west, which means it is a scheduling input on a great many parcels rather than an edge case.
- Authorization before mobilization, not on the day. The airspace position is resolved and stated in the proposal. A crew does not leave Red Hook to find out on site whether it can fly.
- The parcel decides it, not the island. Two sites a mile apart can sit inside and outside the surface area. Send the parcel at scoping and the answer comes back with the fee, along with what it does to the delivery date.
- FAA Part 107 throughout. Every flight, inside controlled airspace or not.
- It affects the date, not the deliverable. Where authorization moves a flight, the proposal says so up front. What lands at the end is the same file, at the same 0.10 ft horizontal and vertical on a well-controlled site.
Getting to your site
We are already here.
The office is at 6501 Redhook Plaza, at the east end of the island. For aerial capture, scanning, and site documentation that means same-day mobilization anywhere on St. Thomas: no ferry, no barge, no waiting on a flight with equipment in the hold, and no mobilization line on the fee.
Construction layout and staking works differently, and the distinction matters enough to repeat on every page it touches. Those crews mobilize from the mainland with Trimble total stations and the work is scheduled in advance and priced against that mobilization. It is not an on-demand local call-out and we will not describe it as one. How it is scoped sits on the drone survey page.
The constraint a mainland crew would not plan for is the road. Getting to a hillside site here frequently means a single-lane switchback with no verge, a gate, and nowhere to leave a vehicle within sight of the work. Staging is a real question on this island, not a formality: where a crew can park, whether a truck can turn, and whether the last two hundred feet has to be walked in with the equipment. We plan the approach with the capture rather than discovering it on arrival, which is the difference between a half-day job and a wasted one.
What we do here
The same four disciplines, changed by the island.
Every one of them behaves differently on St. Thomas than it would on flat ground with open sky.
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/01
Drone Survey
On a benched hillside the cut volume is the whole commercial argument, and it is the measurement a ground crew struggles most to get safely. Flying it is faster, safer, and produces a surface both sides can check.
Drone survey services → -
/02
Aerial Mapping
Relief is the complication here. Ridge to shoreline inside a short horizontal distance means a single flight altitude yields very different ground sample distances, so altitude is planned to the terrain rather than to the parcel outline.
Aerial mapping services → -
/03
360° Job Walkthrough
On a lot built to its boundary, the condition of the property next door is part of your risk. A dated record of adjacent structures before you mobilize is worth more in the Charlotte Amalie core than almost anywhere else.
360° walkthrough services → -
/04
Scan to BIM
Historic masonry altered across a century, with whatever drawings exist bearing little relation to what is standing. Scanning measures the building rather than trusting the file, which on this stock is the only defensible starting point.
Scan-to-BIM services →
By site type
What each kind of St. Thomas site actually needs.
A scoping shortcut. Find the row that looks like your job and you will know most of what the proposal is going to say.
| Site type | What makes it hard here | What the job usually needs |
|---|---|---|
| Hillside residential | Steep cut, limited staging, single-lane access | Pre-cut and post-cut surfaces, cut/fill, access planned with the capture |
| Retaining structures | The face disappears once backfilled | Capture before backfill and again as built, with deviation against design |
| Charlotte Amalie core | Party walls, poor sky view, no surviving drawings | Total-station control, adjacent-condition record, scan to BIM |
| Harbour and waterfront | Water-structure interface, weather-bound windows | Aerial plus terrestrial capture, schedule contingency stated up front |
| Port and cruise facilities | Facility-controlled access and operating restrictions | Clearance settled at scoping, capture windows agreed with the facility |
| Road and utility corridors | Long, narrow, switchbacked, expensive to walk | Corridor flight, cross-sections and profiles for the civil team |
Questions we get
About working on St. Thomas.
How quickly can you get to a site on St. Thomas?
Same day for aerial capture, scanning, and site documentation. The office is at Red Hook, so nothing about that work waits on a ferry, a barge, or a flight.
Construction layout and staking is the exception and it is worth saying so here rather than letting the rest of this answer imply otherwise: those crews mobilize from the mainland and the work has to be scheduled in advance. See drone survey for how that is scoped.
Does a flight near the airport need authorization?
Inside the Class D surface area around Cyril E. King, yes, and it needs to be in hand before the crew leaves rather than pending on the morning of the flight.
That area covers a meaningful share of the developed south and west of the island, so the honest answer for a lot of St. Thomas parcels is that airspace is a scheduling input, not a formality. Send the parcel at the scoping call and the airspace position is stated in the proposal, along with what it does to the date.
Can you survey a hillside site a ground crew cannot safely walk?
That is most of what this island asks for. Slopes steep enough to make a conventional topo survey slow, expensive, or genuinely unsafe are exactly where flying pays for itself.
The caveat is vegetation rather than gradient. Bush on a steep face hides the ground from the camera, and a surface built from that reads high. Where the slope is covered we set control and take ground shots through the gaps, and the deliverable states which areas are photogrammetric and which are ground-surveyed rather than presenting one surface as though it were uniform.
What about the dense historic core of Charlotte Amalie?
Tight lots with party walls and shared boundaries are a scanning problem more than a flying one. Between close buildings the sky view is poor, which degrades GNSS, so control comes off the total station instead.
The other constraint is that on a party wall your survey and your neighbour’s reality are the same wall. Capturing adjacent condition before work starts is worth more here than anywhere else on the island. For interiors and structures that have been altered repeatedly without a record, that is scan to BIM.
Do you work over the harbor and the port facilities?
Marine and waterfront work is within scope: bulkheads, docks, revetments, and the land side of terminal facilities.
Access is the part to settle early. Port and cruise facilities run their own access control and their own operational restrictions, and those are set by the facility rather than by us. Tell us at scoping which facility and which areas, and the proposal states what clearance the work depends on instead of assuming it will be arranged on the day.
Elsewhere in the territory
The other two are different jobs.
Not the same page with a name swapped. Terrain, access, and airspace change what the work looks like on each island.
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St. Croix
Larger, flatter, and more open. Area is the constraint rather than access, and inter-island mobilization becomes a real line in the schedule rather than a non-issue.
Construction survey on St. Croix → -
St. John
National Park adjacency shapes the flight plan before anything else does, canopy is heavier, and barge logistics decide when equipment can reach the site at all.
Construction survey on St. John →
Tell us about the site.
Send the island, the parcel, and what you need out the other end. We’ll come back with a scoped, fixed-fee proposal within one business day.