During December 2024, Jeff focused on improving geospatial data reliability in the valhalla/valhalla repository by addressing a critical issue in isochrone GeoTIFF serialization. He corrected the geotransform calculation and data writing loop to ensure all outputs are consistently oriented north-up, resolving previous misalignment problems that affected downstream data consumers. Using C++ and leveraging his expertise in geospatial data processing and testing, Jeff also developed a dedicated test case to verify the vertical orientation and prevent future regressions. His work demonstrated careful attention to data integrity and maintainability, delivering a targeted, well-tested fix within a short project timeframe.