Fix numerical instability in ECEF to geodetic coordinate conversion#1124
Merged
olemke merged 3 commits intoatmtools:mainfrom May 5, 2026
Merged
Fix numerical instability in ECEF to geodetic coordinate conversion#1124olemke merged 3 commits intoatmtools:mainfrom
olemke merged 3 commits intoatmtools:mainfrom
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- Add near-pole threshold detection to handle cases where horizontal distance from z-axis is smaller than 1e-15 * semi-major axis - Add maximum iteration limit (100) with error handling to prevent infinite loops in edge cases
riclarsson
reviewed
Apr 30, 2026
riclarsson
reviewed
Apr 30, 2026
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| add_test(NAME "cpp.fast.test_path_point" COMMAND test_path_point) | ||
| add_dependencies(check-deps test_path_point) |
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You add this again. Was this the reason for the previous failure, then?
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It was consistently failing on Windows (not sure if it errored out or got stuck in the endless loop). Since the fix, I haven't seen any failures reoccurring which leads me to believe this was the culprit.
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This PR fixes a numerical instability in the ECEF to geodetic coordinate conversion algorithm. The previous implementation used an exact equality check (
ecef[0] == 0 && ecef[1] == 0) to detect points on the poles, which was both numerically unstable and failed to handle near-pole cases. These near-pole cases could cause the iterative algorithm to enter an endless loop. To safeguard against any other edge cases that might still be overlooked, additional convergence protection was added.Changes
src/core/geodesy/geodetic.cpp:near_pole_threshold_ecefconstant to detect near-pole points using a threshold-based approach instead of exact equalitymax_ecef2geodetic_iterconstant to prevent endless loops in the iterative conversion algorithmsrc/tests/CMakeLists.txt: Reenabled thetest_path_pointtest that was previously disabled (commit c94deff part of Improve format #773)