treeIDW

treeIDW is a Python library for performing Inverse Distance Weighting (IDW) interpolation using an efficient KD-tree-based selection strategy.
It is designed to be easy to use for newcomers while offering fine-grained control and performance-oriented options for advanced users in numerical methods and spatial data analysis.

Key Features

• Efficient IDW interpolation using KD-tree nearest-neighbor selection
• Automatic exclusion of boundary nodes with negligible contribution
• Optimized numerical kernels powered by numba
• Scalable to large datasets (millions of interpolation points)
• Simple API with expert-level tunable parameters

Installation

treeIDW is available on PyPI.

pip install treeIDW

Development installation (from source)

git clone https://github.com/Dorian210/treeIDW
cd treeIDW
pip install -e .

Dependencies

The core dependencies are:

• numpy
• scipy
• numba

These are automatically installed when using pip.

Package Structure

• treeIDW.treeIDW
  Core IDW interpolation engine.
  Uses a KD-tree to select only boundary nodes with significant influence, improving both accuracy and performance.

• treeIDW.helper_functions
  Low-level, performance-critical routines for IDW weight computation.
  Implemented with numba, including vectorized and parallelized variants.

• treeIDW.weight_function
  Definition of the IDW weight function.
  The default implementation uses inverse squared distance, but custom weight laws can be implemented if needed.

Examples

Example scripts are provided in the examples/ directory:

• Graphical demonstration
  Interpolation of a rotating vector field inside a square domain.

• Large-scale computation
  Propagation of a scalar field from 1,000 boundary nodes to 1,000,000 internal points, highlighting scalability.

• Logo generation
  The generation process of the treeIDW logo itself, where the letters “IDW” are encoded as a vector field and interpolated on a 2D grid.

Documentation

• Online documentation: https://dorian210.github.io/treeIDW/
• API reference is also available in the docs/ directory of the repository.

Contributions

This project is currently not open to active development contributions.
However, bug reports and suggestions are welcome via the issue tracker.

License

This project is distributed under the CeCILL License.
See LICENSE.txt for details.