How to Interpret and Export Data from a Survey Data Collector

Applies to: Trimble TSC3/TSC7/T7, Topcon FC-6000/FC-5000, Leica CS20/CS35, Sokkia SHC5000

The data collector is the brain of the survey crew — it stores every point, raw observation, and setup record from the field. Knowing how to read what the data collector stores and export it correctly to office software is the difference between a smooth deliverable and hours of manual data recovery. This guide covers the structure of data collector jobs, what each file type means, and the correct export workflow for the major platforms.

Understanding the Job Structure

Every survey session is organized as a "job" in the data collector. A job contains the coordinate system (datum, projection, geoid model), the control point database, all collected points with their codes and attributes, raw instrument observations, and the stakeout report if points were set out. On Trimble TSC3/7 running Access software, jobs are stored as .job files. On Topcon FC-6000 running MAGNET Field, jobs are .mjf files. On Leica CS20 running Captivate, jobs are .lsd files.

Before exporting, confirm you are in the correct job. It is common on busy sites to have multiple jobs open — one for topographic collection, one for stakeout, one for as-built. Export from the wrong job exports the wrong data. Always verify the job name, date, and control points before beginning the export workflow.

Reading the Point List

Open the point manager or point database in the data collector. Each point record shows: point name or number, northing, easting, elevation, and description/code. Review the code column for completeness — every point should have a meaningful code (MINV, MRIM, EDGE, CORN, etc.) that allows the CAD operator to process the data correctly. Points with no code or a default code ("P1", "P2") require manual intervention in the office.

Check for duplicate point names. If two points share the same name, the data collector typically shows the most recent measurement, but the older reading may be in the raw file. Duplicates often indicate a remeasure or an error — review both readings before exporting. Also check for points with elevations that appear out of range — a zero elevation or a value far outside the project range usually indicates a pole height was entered incorrectly.

Checking the Coordinate System

The coordinate system setting in the data collector defines what the exported coordinates mean. Verify: projection (State Plane, UTM, or site-specific), datum (NAD83, WGS84, or local), and geoid model (GEOID18, GEOID12B) before exporting. A coordinate system mismatch — exporting NAD83 State Plane data into a WGS84 project — produces systematic position errors that can exceed one meter and are not obvious until a check shot fails.

On Trimble Access, coordinate system is in the job properties under "Coordinate System." On MAGNET Field, check "Coordinate System" in the job settings. On Leica Captivate, find it in "Project Properties." If the coordinate system is listed as "No Projection" or "Ground," the data is in a local or assumed coordinate system — confirm with the project engineer before sending to the office.

Exporting Points and Raw Data

For point export, the most universally compatible format is CSV (comma-separated values) with columns: point name, northing, easting, elevation, code. Most data collectors offer a customizable CSV export — confirm the column order matches what the office software expects. For CAD, DXF export preserves point codes as layer names, which simplifies drawing cleanup. LandXML is the best format for importing into Civil 3D or MicroStation because it carries coordinate system metadata with the points.

Raw observation files (.RAW for Trimble, .RAW for Sokkia, .raw for Topcon) contain every angle and distance measured by the total station before coordinate computation. These are required for surveying that must be submitted with raw data to a licensing board or agency. Export raw files whenever the survey will be used for legal purposes, boundary work, or formal as-built submittals.

Transferring to Office Software

Connect the data collector via USB cable or Wi-Fi. On Trimble TSC devices, the data collector mounts as a removable drive in Windows Explorer — navigate to the JOBS folder and copy the .job file. Use Trimble Business Center to open and process. For Topcon FC series, use MAGNET Office to connect via USB or Bluetooth and sync the job database. For Leica CS20, use Leica Infinity to import from the device. Most platforms also support cloud transfer — Trimble Connect, Topcon MAGNET Enterprise, or Leica ConX — for wireless job sync without a USB cable.

After transfer, open the job in the office software and run a quick visual check: zoom to the extent of the data and confirm it falls in the correct geographic location. A job that appears in the wrong country or the wrong state usually has a coordinate system error that must be fixed before proceeding to production.

Frequently Asked Questions

What is the difference between a raw file and a coordinate file from a data collector?

A raw file contains the original field measurements — angles, distances, and instrument/target heights before any coordinate computation. A coordinate file contains the computed northing, easting, elevation, and code for each collected point. Raw files are used for survey adjustments, error detection, and legal submittals. Coordinate files are used for CAD, design, and reporting.

How do I fix a coordinate system error in a data collector job?

On Trimble Access, you can change the coordinate system in job properties before exporting — but only if you have the correct system available. On MAGNET Field, the coordinate system can be reassigned in job settings. If points were already collected in the wrong system, you may need to apply a coordinate transformation in office software rather than in the data collector.

What does "residual" mean on a data collector stakeout screen?

A residual is the difference between the design point coordinates and the actual staked point location. The data collector displays horizontal residual (how far the stake is from the design position) and vertical residual (how far the stake elevation is from the design elevation). Residuals are recorded in the stakeout report for contractor and inspector documentation.

Can I transfer data collector files without the manufacturer's software?

Yes for most platforms. Trimble .job files are transferable as raw files and can be parsed by third-party software. Topcon .mjf files can be exported to standard formats (CSV, DXF, LandXML) from the device without MAGNET Office. However, using the manufacturer's office software is recommended for preserving all metadata, raw observations, and coordinate system information.