InfoTown™
Stevie's journey · Engineering · Lesson 3

Whose co­ordinates?

Before you start

In the story

Two firms, two sets of pins, and a pipe that missed by 300mm.

Back to the story

The right way

Before anyone sets out

The job's survey control goes into the shared kit on the CDE: the coordinate system, the height datum and the control stations, with a revision.

Each firm's day one

Every firm gets the control before it starts, and Stevie walks their engineer round the stations. Old pins from earlier surveys come out, or get sprayed NOT FOR SETTING OUT.

Week five

The pipe meets the chamber. Rex: "That's a bit boring." Stevie: "Boring's the job, son."

Pins in the grassTwo grids, one pipe 300mm out, and two weeks digging it up again.
One control, issued and checkedEvery firm on the same pins, checked on day one, and a pipe that meets its chamber.
Think like Stevie

Before you set out anything, can you say which control, which coordinate system and which height datum you're working from, and where it's written down? If you can't say it in one breath, stop and check.

Continue Stevie's journey

Story 4: Ask the designer

Rex asks the designer a question in a phone chat. He gets the right answer. Nobody else ever sees it.
The right way, explained

The right way, explained

Every town agrees where its streets start from. If two builders measure from different corners, their walls won't meet in the middle, however carefully each of them measured.

If you're the designer

If you're the designer

Model on the job's coordinates from day one and say so on every drawing. If you need a local grid to make sense of a building, show how it ties to the job's.

In the town See it in the town: two firms, two sets of pins. Whose town are we measuring?

Stevie's view: the setting-out pins are part of the kit handed out at the Site Office, the same for every firm that turns up.

The towns meet at the project site Your town, Designer Town and Client Town each stay where they are. Roads from all three lead into one shared project site in the middle, with a Site Office being built and a sign saying for this job only. DESIGNER TOWNYOUR TOWNCLIENT TOWN THE PROJECT SITESITE OFFICE THIS JOB ONLY stays where it isstays where it isstays where it is everyone worksthrough the site

Now mobilise it: build and connect the site

In the middle sits the Site Office: the project's CDE, joined to your own Records Office by the home line. Lines run out to every town: the design line to the designers, the client line to the client, the home line back to your own Records Office, the feeder line to the site apps and footpaths to the cabins. The workflows running along all these lines are how one system passes work to another. Signposts tell everyone where each kind of work goes, and the gate decides who gets in.

  1. Build the Site Office
  2. Connect the towns
  3. Plug in the site apps
  4. Put up the signposts
  5. Set up the gate
  6. Test everything

The towns are there. The project site is an empty plot. Your job: mobilise it.

The project site, connected A project site with the Site Office (the project CDE) at its centre. A design line runs to Designer Town, a line runs to the Client Town, a line runs home to your town's Records Office, a feeder line runs to the site apps, and footpaths lead to the site cabins. Signposts show where drawings, photos, RFIs and approvals go. A gate at the edge of the site controls who gets in. PROJECT SITE DESIGN LINE CLIENT LINE HOME LINE FEEDER LINE DESIGNER TOWN DESIGN SYSTEM CLIENT TOWN YOUR TOWN RECORDS OFFICE CDE SITE OFFICE SITE CABINS SITE APPS MOBILISED ✓ Drawings → Site Office ← Paper? Scan it in Site photos → app ← Visitors: sign in here Approvals → client line
Design line. To and from the designers.
Home line. Back to your own Records Office.
Client line. To and from the Client Town.
Feeder line. What's captured on site must reach the Site Office: by hand, on a schedule, through a link between systems, or because the app is part of the CDE.

These are Shared Resources!

The same kit for every firm, handed out before anyone starts: templates, title blocks, and the job's one set of coordinates.

Sam's Heads Up Your job might have three grids

InfoTown good practice: One coordinate system for the job, issued to everyone.

On your job: There may be a national grid, a site grid and a structural grid. That's fine, as long as someone has written down which one wins and how the others tie to it.

For the audit What the auditor will ask
  • Which coordinate system and survey control does this job use, and how did each firm get them?
  • How do you know a new firm's setting out matches yours?
For the audit What good evidence looks like
  • The survey control in the shared kit, with a revision and a date.
  • A record of each firm checking into the control before it started.
From the standard
ISO 19650 Shared resources

ISO 19650 expects the shared resources a team needs to be provided before production starts. That the job's coordinates and survey control belong in that kit is InfoTown's advice, not a quote.

Based on the ISO 19650 series: the ideas come from the standard; the plain-English wording, examples and advice are InfoTown's. ISO 19650 is © ISO and BSI. You'll hear the same language across the industry. Read more for free in the Information Management Initiative (IMI) Framework guidance from BSI and nima. For the full requirements, use the standard itself.