How to Prepare Project Files for iCON Layout
To prepare iCON layout files, you need three things: control points saved as a .CSV or .TXT file, cleaned-up linework saved as a .DWG or .DXF file, and (when you have them) layout points saved as a .CSV or .TXT file. All of them must be current, in the same coordinate system, and in the units you plan to use in the field. If you get those three files right, setting up the instrument and loading the tablet usually goes quickly. If you get them wrong, the first hour on site goes to fixing files instead of laying out.
This guide covers the same file preparation steps that Datum covers before every on-site total station training session. That page also offers our two iCON prep PDFs, so you can keep the checklist handy.
The three iCON layout files
An iCON tablet works with the same three core file types whether it's running a robotic total station or a GPS rover. Here's each one and why it's there.
| File | Format | Shows up as | Who usually provides it |
|---|---|---|---|
| Control points | .CSV or .TXT | Grey triangles | The project surveyor |
| Drawings / linework | .DWG or .DXF | Linework and background | Design team, GC or trade BIM group |
| Layout points | .CSV or .TXT | Grey circles | Trade detailer or BIM group |
1. Control points
Control points tie the instrument to the project. With a total station, you set up on or resect from these points before you lay anything out. Ask the surveyor for them as a plain .CSV or .TXT file, not a PDF of a control sheet. When you import an ASCII file, iCON lets you pick the field separator, skip header rows and set the distance units. Check those settings carefully, because a wrong column order or unit can silently put every point in the wrong place.
2. Drawings and linework
Linework such as grid lines and structural elements can come in as .DWG or .DXF, and crews can lay out directly from it. iCON can import many formats, but a clean, layout-ready file is what makes the tablet fast in the field. Include:
- The project grid, always.
- Only the linework you need in the field for this task, such as structural, piping or HVAC references.
Remove hatches, annotations, dimensions, title blocks and other detail no one will stake. Large or complex drawings can slow the tablet down. The old guideline of about 10,000 KB is a practical warning sign, not a hard limit. If a file is heavy, iCON lets you deselect layers during import, but it's better to purge the file before it reaches the field. Also keep in mind that DWG files may be converted to DXF when they're imported.
Two DXF import settings are worth knowing. First, if the file specifies its units, iCON reads them, and it warns you when you pick a different unit. Second, by default, points with a zero elevation come in as 2D points ("Ignore Null Heights"). That's usually what you want for plan layout, but it's worth checking if your elevations matter.
3. Layout points
Layout points are for items that have exact defined locations, with anchor bolts as the classic example. Export them as a .CSV or .TXT file with point IDs that match the drawings. If no point file exists, talk with the layout team. Some work can be laid out directly from good linework, and some really needs points.
Get the coordinate system right before you go
This is where most problems with iCON layout files start. The survey, the GC and the trade BIM files can each be in a different coordinate system. Before anyone goes to site, open all three files together in your CAD or BIM software and confirm:
- The control points, linework and layout points overlay each other correctly.
- Every file uses the units you plan to work in, and feet versus US survey feet is settled.
- The horizontal orientation matches. The grid shouldn't be rotated in one file and square in another.
- The elevations use the same datum.
If the files don't line up, stop. Have the survey or BIM team responsible for the files fix the discrepancy before layout or training. Patching it in the field just moves the error into concrete.
Plan your control for the instrument you're using
Robotic total station
The control points need to be spread across the work area. That way the operator can set up and still see both the control and the area being laid out. More points give more flexibility on large areas when you move between setups. On a rectangular deck, control near each corner is a practical starting point, and longer decks benefit from extra points along the sides. The points need to be identifiable, stable and accessible. Our iCON Setup Anywhere video shows how a free station setup uses that control.
GPS / GNSS rover
With GPS, a site localization links satellite positions to the project coordinates. Use stable ground points that the rover can occupy directly, such as pins or scribed marks. Wall-mounted sticker targets and prisms don't work for this. Spread the points around the site instead of bunching them in one corner, add a few extra for redundancy, and stay clear of buildings that block or reflect the signal. Review the localization results and run an independent check before you start layout. Laying out outside the area enclosed by your localization points needs extra checking when tight tolerances matter.
GPS isn't limited to ground level, but whether it works above grade depends on your accuracy needs, your control and the sky view. For obstructed or elevated work, verify the results or use a total station instead.
A pre-mobilization checklist
- Control points received as .CSV or .TXT, with the point ID, northing, easting and elevation order confirmed.
- Linework purged down to the grid and the layers needed for this scope, and saved as .DWG or .DXF.
- Layout points exported as .CSV or .TXT, or a plan agreed on for working from linework.
- All files overlaid in the office, with units, orientation and elevations confirmed.
- File sizes reasonable, with the large drawings split or trimmed.
- Control locations checked on site: still there, stable and visible from the planned setups.
- Files loaded onto the tablet and a test import run before the crew arrives.
For step-by-step help on the tablet, see the iCON file import video and the rest of our Leica iCON field tutorials.
Back-check before you lay out
Once you've set up, measure a known control point or grid intersection and compare it with the file. This one check confirms that the control, the files and the physical building all agree. If it's out, find the cause before you mark anything. For more habits that save time on site, read 4 Leica total station tips.
FAQ
Can iCON import a PDF of the drawings?
Current iCON software can import 2D PDFs as reference data. Clean DWG or DXF linework is still the better choice for layout, because you can snap to it and stake from it.
What if the surveyor only sends a control sheet?
Ask for the points as a .CSV or .TXT file. Typing coordinates in by hand invites errors that are hard to find later.
Should we bring files to training?
Yes. Datum trains on your own instruments and your real project files, so having them ready means the session is spent learning the work you'll actually do.
Book training with your own files
When your files are ready, request on-site training on the total station training page. Tell us how many people need training, where the site is, and whether your control, linework and layout points are prepared. If they aren't, our prep PDFs on that page will help you get there.