PlotFDM - FDM Seismic Data Visualization Tool

A Python tool for reading and visualizing FDM (Finite Difference Modeling) seismic data files with intelligent plotting capabilities.

Features

• FDM File Format Support: Read FDM binary files with 512-byte headers
• Intelligent Plotting: Automatic colormap selection (TgsBanded for velocity, gray_r for seismic)
• Smart Scaling: Automatic RMS -4dB scaling with seismic power dB convention
• Interactive Controls: Real-time gain/dim adjustments with keyboard shortcuts
• Custom Colormaps: BigTiger and TgsBanded colormaps for seismic visualization
• Multiple Views: Single slice or summary plots with all three axes
• Flexible Coordinates: Support for both logical (grid) and physical coordinates
• Manual Scaling: Override automatic scaling with custom min/max values

Sample Data

The repository includes sample FDM files in the examples/ directory:

• examples/shot_topo.fdm - Seismic shot data with topography
• examples/vel_topo.fdm - Velocity model with topography

Try them out:

python plotfdm.py examples/shot_topo.fdm --summary
python plotfdm.py examples/vel_topo.fdm --summary

Installation

git clone https://github.com/YOUR_USERNAME/plotfdm.git
cd plotfdm
pip install -r requirements.txt

Dependencies

• Python 3.6+
• NumPy
• Matplotlib
• Custom colormaps module

Usage

Basic Usage

# Plot middle Y-slice with automatic settings
python plotfdm.py data.fdm

# Show summary with all three axis slices
python plotfdm.py data.fdm --summary

# Plot specific slice
python plotfdm.py data.fdm --slice z --index 10

# Use physical coordinates instead of logical
python plotfdm.py data.fdm --physical

Advanced Options

# Manual colormap scaling
python plotfdm.py data.fdm --vmin -100 --vmax 100

# Custom colormap
python plotfdm.py data.fdm --cmap viridis

# Save to file instead of displaying
python plotfdm.py data.fdm --save output.png

# Show file info only
python plotfdm.py data.fdm --info

Interactive Controls

When displaying plots interactively, you can use keyboard shortcuts:

• g - Gain +1.5dB
• gg - Gain +3.0dB (press g twice quickly)
• d - Dim -1.5dB
• dd - Dim -3.0dB (press d twice quickly)

File Structure

• plotfdm.py - Main plotting tool with CLI interface
• fdm.py - FDM file format reader class
• custom_colormaps.py - Custom colormap definitions

FDM File Format

The tool supports FDM files with:

• 512-byte binary headers
• 3D data arrays with (ny, nx, nz) memory layout
• Physical coordinate conversion
• Automatic data type detection

Automatic Scaling

The tool uses intelligent defaults:

• Colormap Selection: TgsBanded for velocity data (all positive), gray_r for seismic data (pos/neg)
• Scaling: RMS -4dB using seismic power dB convention (10^(±dB/10))
• Coordinates: Physical coordinates for Z-axis (depth), logical coordinates for X/Y by default

License

MIT License - see LICENSE file for details

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Submit a pull request

Author

Created for seismic data visualization and analysis workflows.