DXF-Reprojection

A user-friendly command-line tool for reprojecting coordinates in DXF (AutoCAD) files from one coordinate reference system (CRS) to another.

Overview

This tool parses DXF files, identifies coordinate sets in AcDbFace and 3DFACE sections, reprojects the X and Y coordinates using pyproj, and writes out new DXF files with the updated coordinates.

Installation

1. Clone this repository:

git clone https://github.com/RichardScottOZ/DXF-Reprojection.git
cd DXF-Reprojection

2. Install dependencies:

pip install -r requirements.txt

Usage

Basic Usage

Reproject a single DXF file:

python dxf_reproject.py -i input.dxf -o output.dxf -s EPSG:20254 -t EPSG:28354

Reproject all DXF files in a directory:

python dxf_reproject.py -i ./input_dir -o ./output_dir -s EPSG:20254 -t EPSG:28354

Command-Line Options

  -i, --input INPUT          Input DXF file or directory containing DXF files
  -o, --output OUTPUT        Output DXF file or directory for reprojected files
  -s, --source-crs CRS       Source coordinate reference system (e.g., EPSG:20254)
  -t, --target-crs CRS       Target coordinate reference system (e.g., EPSG:28354)
  --suffix SUFFIX            Suffix to add to output filenames (default: extracted from target CRS)
  --overwrite                Overwrite existing output files without asking
  -h, --help                 Show help message and exit

Examples

Example 1: Convert from AGD66 to GDA94

python dxf_reproject.py -i survey.dxf -o survey_gda94.dxf -s EPSG:20254 -t EPSG:28354

Example 2: Batch process multiple files

python dxf_reproject.py -i ./original_files -o ./reprojected_files -s EPSG:20254 -t EPSG:28354

Example 3: Use custom suffix

python dxf_reproject.py -i ./input -o ./output -s EPSG:20254 -t EPSG:28354 --suffix wgs84

Common EPSG Codes

• EPSG:4326 - WGS 84 (GPS coordinates)
• EPSG:3857 - Web Mercator (used by Google Maps, OpenStreetMap)
• EPSG:28354 - GDA94 / MGA zone 54 (Australia)
• EPSG:20254 - AGD66 / AMG zone 54 (Australia, legacy)
• EPSG:32754 - WGS 84 / UTM zone 54S

You can find more EPSG codes at epsg.io

Features

• ✅ User-friendly command-line interface
• ✅ Support for single file or batch directory processing
• ✅ Progress bars for batch operations
• ✅ CRS validation before processing
• ✅ Error handling and informative messages
• ✅ Automatic output filename generation with CRS suffix
• ✅ Safety check to prevent overwriting files accidentally

How It Works

The tool uses a text-based parsing approach:

1. Reads the DXF file as text
2. Identifies coordinate sections marked by AcDbFace and 3DFACE tags
3. Extracts X, Y coordinate pairs
4. Reprojects coordinates using pyproj's Transformer
5. Replaces original coordinates with reprojected values
6. Writes out the updated DXF file

Note: This approach works well for files with reasonable numbers of coordinates. For DXF files with millions of coordinates, consider a vectorized/parallelized version for better performance.

Jupyter Notebook

The original Jupyter notebook (DXF-Parsing.ipynb) is still available for interactive use and experimentation.

Requirements

• Python 3.6+
• pandas
• pyproj
• tqdm

License

This project is open source. Please check the repository for license details.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.