Free GSSI DZT Files — Ground Penetrating Radar Sample Data
Download real DZT sample files, learn what the format contains and how to open it
The DZT file format is the native data format of GSSI (Geophysical Survey Systems, Inc.) Ground Penetrating Radar systems — the most widely used GPR equipment in the world. Every GSSI acquisition produces DZT files containing the raw radar traces, acquisition parameters, and positioning information recorded in the field.
GPRbase provides free DZT sample files from real surveys: reinforced concrete inspections, underground utility detection, geotechnical investigations, archaeology, and more. All files are raw, unprocessed data — exactly as recorded by the equipment. They are distributed under Creative Commons BY-NC-SA 4.0 for education, research, software development, and testing.
Whether you are developing DZT-compatible software, learning GPR data processing, testing a parser, or teaching radargram interpretation, these authentic sample files give you real-world signal complexity that synthetic data cannot provide.
Free DZT sample files
Every dataset below contains raw .DZT files — download and explore — 17 datasets available
Confirmed Karst Cavities in Limestone — 300 MHz GPR Profiles to 4 m Depth
Raw GPR profiles acquired over limestone containing confirmed karst cavities, using a GSSI UtilityScan DF dual-frequency antenna. The 300 MH…
Reinforced Concrete Slab with Expansion Joint
GPR dataset containing 7 files collected on a reinforced concrete slab using a GSSI FLEX NX structure-scanning radar. The data clearly show …
Utilities & Interfaces in Favorable Soil with Deep GPR Penetration
GPR dataset containing 1 file collected with a GSSI UtilityScan DF dual-frequency 300/800 MHz ground penetrating radar in highly favorable s…
Ground-penetrating radar detection of gas connections (HDPE polyethylene)
4 dual-frequency ground-penetrating radar profiles (UtilityScan DF) showing the location of HDPE (High-Density Polyethylene) gas connections…
3D concrete scanning over a slab-access ramp interface
60 x 60 cm 3D grid (10 cm spacing). Starting point at bottom left (0,0) and profiles from left to right, then from bottom to top. Try to rec…
Detection of various buried utilities using a dual-frequency antenna (300 MHz and 800 MHz) Highway pavement inspection along an emergency stopping lane (ESL)
One GPR profile across an avenue, crossing several buried utilities. How many do you see?…
Two layers of rebars in a reinforced concrete structure (3D grid)
26 profiles (60 x 60cm grid), 5cm spacing. Ideal dataset for practicing 3D processing with GPRviewer, and easier to see the best possible re…
Roadway inspection along an emergency stopping lane (ESL)
Six dual-frequency ground-penetrating radar (GPR) profiles (300/800 MHz) showing numerous interfaces and pavement structure layers in a soil…
Thickness detection above three masonry bridge arches
Ground-penetrating radar measurements recorded with UtilityScan DF 300/800 MHz from the roadway…
Detection of buried pipes with the NX15 step-frequency ground-penetrating radar antenna
High resolution imaging with the NX15 antenna, for detecting buried cables and pipes. Observe the data quality, ideal for locating small-dia…
Voids in a concrete block wall
FLEX NX file, dual antenna (inline & cross-line), created on a concrete block wall with gaps (no concrete) at the end of the profile. Test t…
3D Grid Concrete bloc wall with voids
3D grid 60x60 cm created with the FLEX NX radar, 3D mode (26 profiles per antenna) Spacing : 5 cm Origin (0,0) : bottom-left…
Georeferenced dual-frequency ground-penetrating radar (GPR RTK) files
16 Radar profiles in a parking lot, showing heterogeneous soil conditions. The data is georeferenced and can be imported into GPRviewer for …
FLEX, NX25 and NX15 reference lines (MDSLab)
Three radar profiles were created on the same line, one of our reference lines in the MDSLab in Aix-en-Provence. Compare the measurements of…
Double layer of reinforcement and structural change (1 profile)
One radargram. Two identifiable steel layers, the second being more difficult to discern. A change in structure is also visible before 50 cm…
FLEX 3D grid 60 x 60 cm (reinforced concrete beam and slab).
INLINE (channel 1) and CROSS-LINE (channel 2) profiles: 26 profiles, 13 in X, 13 in Y (5 cm spacing)…
Detection of a backfilled marl pit beneath a road
This profile shows a measurement taken at the level of a roadway, with the presence of a marl pit that has been filled in. Several layers of…
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 license required. GSSI's RADAN software offers full professional processing. Several open-source libraries also read DZT: readgssi (Python), GPRPy (Python), and RGPR (R). For software developers, the DZT header structure is documented in GSSI's SIR system manuals.
DZT file structure for developers
The DZT format starts with a 1024-byte header (or multiples for multi-channel files) containing acquisition metadata: number of samples per scan, bits per sample (typically 16 or 32), scans per second, antenna name, and range in nanoseconds. Raw trace data follows as sequential binary values. Multi-channel systems interleave channel data. Understanding this structure enables custom parsers, batch processing pipelines, and machine learning data loaders.
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.
How to visualize DZT data
A DZT file renders as a radargram: a 2D image where the horizontal axis is survey distance, the vertical axis is two-way travel time (or depth), and pixel intensity represents reflection amplitude. Point targets like rebar appear as hyperbolas; layer interfaces appear as continuous horizontal reflections. GPRviewer displays this rendering instantly, with adjustable gain and color palettes to reveal weak deep reflections.
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.
Frequently asked questions — DZT files
Can I open DZT files without RADAN?
Yes. GPRviewer (free, by MDS) opens DZT files directly. Open-source options include readgssi and GPRPy in Python, and RGPR in R. No GSSI license is needed to read the format.
What is the difference between DZT, DZG and DZX files?
DZT contains the radar data itself (header + traces). DZG contains GPS positions recorded during acquisition. DZX stores project and configuration information. Only the DZT is essential for viewing the radargram.
Can I convert DZT files to other formats?
Yes. Python libraries like readgssi can export DZT data to CSV, numpy arrays, or images. Many GPR processing packages import DZT and export to SEG-Y or their own formats.
Are these DZT files raw or processed?
All GPRbase datasets are raw, unprocessed DZT files — exactly as recorded in the field. No filtering, gain, or migration has been applied, making them ideal for testing processing pipelines from scratch.
Can I use these DZT files to test my own GPR software?
Yes, that is one of their main purposes. CC BY-NC-SA 4.0 permits software testing and development use. Real files from different antennas and site conditions are ideal validation material.
Need to visualize these DZT files?
GPRviewer is a free 2D visualization tool published by MDS. Open any DZT file, adjust gain and filters, measure depths — no license required.
Discover GPRviewer