mth5_viewer — MTH5 Viewer (MATLAB)

A MATLAB App Designer GUI to browse MTH5/HDF5 files used in magnetotellurics (MT): explore the HDF5 hierarchy, inspect attributes/metadata, preview datasets, and export contents to the MATLAB workspace.

Developed in MATLAB R2024b.

---

What is an MTH5 file?

MTH5 is an HDF5-based container format for magnetotelluric (MT) time-series data and associated metadata.
In practice, an MTH5 file is a standard HDF5 file (*.h5) that stores:

• Groups (HDF5 groups): hierarchical folders that organize the content
• Datasets (HDF5 datasets): numeric arrays (time series, derived products, etc.)
• Attributes: key–value metadata attached to groups/datasets (station/run info, sampling parameters, units, processing details, etc.)

Because MTH5 is HDF5, files can be very large (full time-series across many channels/runs), and some metadata may be stored as:

• HDF5 object references (attributes that point to other objects inside the file)

This viewer is designed to make these structures inspectable quickly from MATLAB.

Typical structure (conceptually)

MTH5 commonly follows how MT data are collected:

• survey → stations → runs → channels (and related metadata)

Exact group naming and conventions are defined by the upstream MTH5 project.

---

What this Viewer provides

Current features (implemented)

• Load MTH5 file (*.h5) from the UI: File → Load → MTH5 file (*.h5)
• Tree browser (groups / datasets / attributes)
  • datasets display: name [size] <datatype>
• Description panel
  • group nodes: counts of groups/datasets/attributes via h5info
  • dataset nodes: size + datatype class via h5info
  • attribute nodes: value preview + best-effort HDF5 reference resolution
• Quick-look plot
  • 1D datasets are read using a stride/downsample for plotting (to avoid loading the full vector)
• Export to Workspace
  • File → Export → to Workspace
  • runs a full-read exporter (mth5_export) and assigns tree into MATLAB base workspace

⚠️ Note on memory: mth5_export is a FULL READ by default (datasets read with h5read). Large files can exceed memory. Use it intentionally.

---

Repository layout (current)

MTH5Viewer/
├─ GUI/         # App Designer GUI (mth5_viewer)
├─ Functions/   # loaders/exporters/tree helpers/callbacks
└─ Extras/      # icons + logo assets
   ├─ Icons/
   └─ Logo/

---

Getting started (from source)

1. Clone the repository
2. Add folders to the MATLAB path (example):

root = "C:\path\to\MTH5Viewer";
addpath(fullfile(root, "GUI"));
addpath(fullfile(root, "Functions"));
addpath(fullfile(root, "Extras"));
addpath(fullfile(root, "Extras", "Icons"));
addpath(fullfile(root, "Extras", "Logo"));

3. Run:

mth5_viewer

---

Screenshot

---

Packaging as an App

This project can also be distributed as a MATLAB App (.mlapp) via App Designer packaging.
(If you publish releases, place the .mlappinstall under GitHub Releases and document the steps here.)

---

Documentation

This repo (GitHub Pages)

• https://.github.io/mth5_viewr/

Upstream MTH5 (official)

• Docs: https://mth5.readthedocs.io/en/latest/index.html
• Source (GitHub): https://github.com/kujaku11/mth5

---

How to cite MTH5

Peacock, J. R., Kappler, K., Heagy, L., Ronan, T., Kelbert, A., & Frassetto, A. (2022).
MTH5: An archive and exchangeable data format for magnetotelluric time series data.
Computers & Geosciences, 162, 105102. https://doi.org/10.1016/j.cageo.2022.105102

---

License

MIT License (see LICENSE).