How to Convert CAD Coordinates to a Site Setting-Out List

The gap between CAD and the setting-out peg is where errors live

You've got a CAD drawing — maybe a civil engineering layout, a solar park foundation plan, or a fencing line schedule. The designer hands it over and says the coordinates are all in there. Your job is to get those points pegged out accurately on site. Simple enough in theory. In practice, this step is where projects quietly accumulate errors that only show up later, usually at the worst possible moment.

This article walks through how to extract coordinates from CAD, clean and structure them into a usable setting-out list, validate the data before you go near a GNSS receiver, and create a point record that's actually useful beyond the day of set-out.

Step 1: Export coordinates from CAD properly

Most CAD packages — AutoCAD, Civil 3D, MicroStation — can export point data as a delimited text file or CSV. The problem is that the default export is rarely clean enough to use directly.

Before you export, check:

• Coordinate system: Are the coordinates in the correct national grid or project coordinate system? British National Grid (OSGB36) and WGS84 are not interchangeable. Using the wrong one on site can put you metres out.
• Decimal precision: Survey-grade set-out typically needs three decimal places on Easting and Northing. Truncation to two decimals introduces up to 10mm of error before you've even left the office.
• Delimiter consistency: Some exports mix commas and spaces. Choose one delimiter and stick to it throughout.
• Point IDs: CAD block names or layer prefixes don't always make sensible point IDs. Agree a naming convention before export — something like FND-001, FND-002 — and apply it consistently.

If your CAD file contains block attributes or annotation rather than proper coordinate data, you may need to extract attributes separately and join them to geometry coordinates. This is a common source of mismatch and worth checking explicitly.

Step 2: Structure the setting-out list

Once you have raw coordinate data, it needs to be in a format that's unambiguous and uploadable to your total station, GNSS controller, or site management platform.

A clean setting-out list has five columns, nothing more:

1. Point ID — unique, meaningful, no spaces or special characters
2. Easting — to three decimal places
3. Northing — to three decimal places
4. Elevation — to three decimal places (or a null value if not applicable)
5. Description — short, standardised label (e.g. PILE TOP, FENCE POST, INVERTER BASE)

Keep descriptions consistent. "Fence Post", "fence post", "FP" and "F/POST" all mean the same thing to a person and four different things to any software trying to filter or group by description. Pick one term per feature type and use it throughout.

Strip out any columns that aren't needed — design notes, layer names, colour codes. The leaner the file, the less opportunity for the GNSS controller to choke on unexpected characters.

Step 3: Validate the data before you go on site

This is the step most teams skip, and it's the one that causes the most grief.

Before the file goes anywhere near a surveyor's data collector, run these checks:

• Duplicate Point IDs: Two points with the same ID will either overwrite each other silently or cause an import error. Either way, you lose data.
• Out-of-range coordinates: If your project is in the Midlands, every Easting should be roughly 350,000–550,000 and every Northing roughly 200,000–450,000 (OSGB36). Anything wildly outside that range is a data error.
• Blank cells: A missing Easting or Northing is an unusable point. Flag it before it becomes a conversation on site at 7am.
• Cross-reference against the design schedule: If the engineer issued a coordinate schedule as a separate document, compare Point IDs and values between the CAD export and the schedule. Discrepancies mean one of them is wrong — and you need to know which before you start pegging.
• Point count: Count the points in the CAD export and compare to the design schedule total. If they don't match, something was missed or duplicated in the export.

In Excel or Google Sheets, a simple COUNTIF will catch duplicate IDs. Conditional formatting on Easting and Northing columns can flag values outside expected ranges in seconds. These are five-minute checks that prevent hours of re-work.

Step 4: Add What3Words to every point

Here's something most setting-out workflows ignore entirely: once the peg is in the ground, how does anyone find that exact location again in six months, or six years?

What3Words assigns a unique three-word address to every 3m × 3m square on Earth. Appending a What3Words address to each point in your setting-out list turns it from a one-time construction reference into a lasting location record. Anyone with the free app — a maintenance engineer, a security inspector, a client auditor — can tap the address and navigate straight to it. No coordinate literacy required.

You can generate What3Words addresses in bulk using their API, or by converting coordinates through their web converter. Add the result as a sixth column in your setting-out list and it costs almost nothing in time.

Step 5: Version control the file

Design changes happen. When the engineer issues a revised coordinate schedule, the old setting-out list must not stay in circulation. Name files with a clear version and date — SiteA_SettingOut_v3_2025-06-10.csv — and archive superseded versions rather than deleting them. If a dispute ever arises about which coordinates were used on a particular date, you'll want to be able to prove it.

Store the master file somewhere everyone with a need can access it, and somewhere no one without a need can accidentally overwrite it. A shared drive with version history enabled is the minimum. A proper document management system is better.

Putting it all together

The full process looks like this:

1. Export coordinates from CAD with correct CS, precision and delimiter
2. Standardise into five-column format with consistent Point IDs and descriptions
3. Validate: duplicates, range checks, blank cells, cross-reference against design schedule
4. Append What3Words addresses for lasting location records
5. Version-control and distribute the final file

Done properly, this process takes an experienced person two to four hours for a typical solar park or civils package — and it eliminates the most common category of setting-out errors before the GNSS receiver is even switched on.

When it makes sense to hand this off

If coordinate processing and survey-grade set-out isn't your core business, or if your team is already stretched, it's worth knowing that specialists handle this end to end. Streamtech Setting Out processes CAD and coordinate schedules into clean, validated point lists, sets out on site with GNSS, and stores every point with a What3Words address — so the location record outlasts the project itself. Coordinate processing from £5/point, survey-grade set-out from £10/point.

Whether you handle it in-house or bring in a specialist, the principle is the same: the setting-out list is a data product, and like any data product, its quality determines everything that comes after it.