Free GSSI DZT Files — Ground Penetrating Radar Sample Data

What is a DZT file?

A DZT file is a binary data file produced by GSSI Ground Penetrating Radar systems. It contains a file header (acquisition parameters: antenna frequency, samples per scan, range, dielectric constant settings) followed by the raw radar traces — each trace being a column of amplitude values representing reflected energy versus time. One DZT file typically corresponds to one survey line or one continuous acquisition. Companion files may include .DZG (GPS positions) and .DZX (project configuration).

How to open DZT files?

The simplest free option is GPRviewer, published by MDS: it opens DZT files directly and displays the radargram with gain, filters and measurement tools, no licence required. Geolitix offers online 2D and 3D processing and interpretation, with a free account for small projects. Several open-source libraries also read DZT: readgssi (Python), GPRPy (Python) and RGPR (R). For developers, the DZT header structure is documented in GSSI's SIR system manuals.

Which software opens these files

What a GSSI acquisition contains

An acquisition is not always a single file. The .DZT carries the radar data itself: the traces recorded along the profile and the acquisition parameters. When the survey is georeferenced, a .DZG comes with it, holding the positions recorded during the measurement. A .DZX may be added, describing the project and its configuration.

These files are linked by their base name: renaming one without the others breaks that link, and a georeferenced survey then loses its coordinates. This is why GPRbase archives keep the original names and the folder structure as recorded by the instrument, including the per-channel subfolders of multi-antenna acquisitions.

Compatible GSSI equipment

All GSSI systems produce DZT files: the current FLEX NX (2.5 GHz), NX25 (2.5 GHz), and NX15 (1.5 GHz) for concrete inspection, plus utility detection and geophysical systems across the frequency spectrum. The datasets on GPRbase were acquired with various GSSI antennas — each dataset page specifies the exact equipment and frequency used, so you can find sample files matching your target hardware.

What you can do with these files

A DZT file is displayed as a radargram: an image where the horizontal axis is distance travelled, the vertical axis two-way travel time, and pixel intensity the amplitude of reflections. Point targets such as rebar or pipes appear as hyperbolas, layer interfaces as continuous reflections.

From there, uses diverge. In training, you practise rebar picking, cover measurement, interface tracing and the conversion of travel time into thickness. In development, you test a reader against varied antenna and frequency configurations. In research, you work with raw untreated signal — with the noise, imperfect coupling and ambiguous signatures that a simulation does not reproduce.

Download free DZT sample data

All GPRbase datasets contain raw DZT files, free to download under CC BY-NC-SA 4.0. Use them to test your DZT-compatible software, validate parsers against real multi-antenna data, build teaching material, or train machine learning models. Each dataset documents the antenna, frequency, and targets — pick the samples that match your use case below.

Reading DZT metadata programmatically

For every dataset, the GPRbase catalogue exposes in JSON the antenna used, the frequency, the file count and the survey targets — without opening a single DZT file. Useful for assembling a test set covering several acquisition configurations before developing or validating a reader.

API documentation  ·  /api/datasets.json  ·  GitHub  ·  DOI