A desktop GUI application for curve fitting and data visualization, built with Python. Load your data, select a fitting function, and get statistical results along with plots — all from a simple and clean interface.
- Supports CSV and XLSX data files
- 11 built-in fitting functions: constant, linear, polynomial (degrees 1–5), straight power, inverse power, hyperbolic, exponential, sin, cos, normal, and Poisson
- Real-time equation display for the selected fit
- Dynamic initial guess fields per fitting function
- Statistical results: fitted parameters with uncertainties, chi-squared, degrees of freedom, reduced chi-squared, and p-probability
- Separate plot tabs for Data, Fit, and Residuals — each with customizable title and axis labels
- Save all plots as PNG and fit statistics as a
.txtfile - Adjustable font size (small, medium, large) via the View menu
Requirements: Python 3.8+
- Clone the repository:
git clone https://github.com/dn-stef/datafitter-gui.git
cd datafitter-gui- Install dependencies:
pip install -r requirements.txt- Run the application:
python main.py- Click Choose file or go to File → Upload data file to load a CSV or XLSX file
- The application assumes the first row contains column headers
- The four column dropdowns (X, X error, Y, Y error) are automatically assigned to the first four columns in order — you can change these manually if your file is arranged differently
- Select a fitting function from the Fitting function dropdown
- If you select polynomial, a degree selector appears (1–5)
- The equation for the selected function is displayed in the read-only field to the right
- Optionally fill in initial guesses for the parameters — leaving them blank defaults to 1.0
- Click Fit to run the fit and view the statistical results
- Sample datasets (polynomial, exponential, sine) are included in the
sample_data/folder to try the application straight away.
- Use the Data, Fit, and Residuals tabs to configure and generate each plot
- Each tab has its own title, X label, and Y label fields — if left blank, they default to the column names and tab name
- Click the plot button in each tab to open the corresponding plot
- Important: the Fit and Residuals plots will only reflect the most recent fit. If you change the fit function or parameters, press Fit again before plotting
- Click Choose directory at the bottom to set an output folder
- Click Save to export all three plots as PNG files and the fit statistics as
fit_stats.txt - Note: you must press Fit before saving — otherwise the stats file will be empty and the fit/residuals plots won't have any fit data in them
datafitter-gui/
├── main.py # Entry point
├── assets/ # Logo and other assets
├── gui/ # All GUI components
│ ├── main_window.py # Main panel and logic
│ ├── menu_bar.py # Menu bar
│ ├── plot_panel.py # Data/Fit/Residuals tab panels
│ └── fit_results.py # Fit statistics popup window
├── fitting/ # Fitting engine
│ ├── functions.py # All fitting function definitions
│ └── engine.py # scipy curve_fit wrapper and statistics
├── data/
│ └── loader.py # File reading and column extraction
├── output/
│ └── exporter.py # Saving plots and statistics
└── requirements.txt
- wxPython — GUI framework
- NumPy — numerical operations
- SciPy — curve fitting and statistics
- Matplotlib — plotting
- pandas — data loading
- openpyxl — Excel file support
Inspired by the open-source EddingtonGUI project.
Physics graduate with a focus on data analysis and Python programming. Built DataFitter to expand my skills in GUI development while creating something practical and applicable to real scientific workflows. I enjoy combining physics-oriented thinking with programming to build tools that make data exploration more accessible.
Inspired by EddingtonGUI.
Built with Python, wxPython, and matplotlib.
