DePSI: An Open-Source Python Software Package for PS-InSAR Analysis

Persistent Scatterer Interferometric SAR (PS-InSAR) is a widely used time-series technique for estimating surface deformation from multi-temporal SAR data. The rapidly increasing volume and resolution of SAR acquisitions from modern satellite missions pose significant challenges for scalability and extensibility. Meanwhile, novel algorithms developed by the InSAR community call for the improvement of maintainability of existing PS-InSAR software. 

We present DePSI, an open-source Python software package for PS-InSAR analysis designed to efficiently handle large InSAR datasets while adhering to modern Python software engineering standards. DePSI is based on the established DePSI algorithm originally implemented in MATLAB (van Leijen, 2014), and extends it with a scalable, modular, and community-oriented architecture. 

To address the challenges of large-scale InSAR processing, DePSI is built on Xarray and Dask, enabling efficient manipulation of multi-dimensional datasets and seamless scalability from local laptops to High-Performance Computing (HPC) environments. This design allows DePSI to process large SAR stacks while maintaining memory efficiency and parallel performance. 

DePSI adopts a functional programming–oriented design, facilitating the integration of new PSI algorithms alongside existing conventional methods. Comprehensive user and developer documentation, including example Jupyter notebooks, is provided to lower the barrier for adoption and extension. Modern software quality practices—such as unit testing, continuous integration, and version control—are fully implemented, ensuring robustness and long-term maintainability and fostering community-driven development. 

DePSI aims to provide a scalable, extensible, and high-quality open-source platform for next-generation PS-InSAR research and applications. In our contribution we will present the software design and use, together with example use cases.