This is an automated email from the ASF dual-hosted git repository.
desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git
The following commit(s) were added to refs/heads/geoapi-4.0 by this push:
new aafb312 Do not return NaN for "no convergence" even in the case of
extrapolations, because tests have shown that the `grid.isCellInGrid(x,y)` may
return `false` (i.e. the point seems to be outside the grid) even when in
reality it should have been inside. In other words, we can not be sure that an
"extrapolation" is really outside the grid. The algorithm may have fail to
converge and think that the point is outside even when the point was deeply
inside (not just on the border) i [...]
aafb312 is described below
commit aafb3121a29d583310f55965e8ac06657b514839
Author: Martin Desruisseaux <[email protected]>
AuthorDate: Wed Apr 17 10:36:51 2019 +0200
Do not return NaN for "no convergence" even in the case of extrapolations,
because tests have shown that the `grid.isCellInGrid(x,y)` may return `false`
(i.e. the point seems to be outside the grid) even when in reality it should
have been inside. In other words, we can not be sure that an "extrapolation" is
really outside the grid. The algorithm may have fail to converge and think that
the point is outside even when the point was deeply inside (not just on the
border) if curvatures i [...]
---
.../operation/transform/InterpolatedTransform.java | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/InterpolatedTransform.java
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/InterpolatedTransform.java
index 936e070..b6bc7a8 100644
---
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/InterpolatedTransform.java
+++
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/InterpolatedTransform.java
@@ -589,22 +589,19 @@ public class InterpolatedTransform extends
DatumShiftTransform {
if (!(Math.abs(ex) > tol || Math.abs(ey) > tol))
break; // Use '!' for catching NaN.
}
/*
- * At this point we determined that we need to iterate
more. If iteration does not converge, we may relaxe
+ * At this point we determined that we need to iterate
more. If iteration does not converge, we may relax
* threshold in last resort but nevertheless aim for an
accuracy of 0.5 of cell size in order to keep some
- * consistency with forward transform. If the point was
inside the grid, we assume (for well-formed grid)
- * that iteration should have converged. But during
extrapolations since there is no authoritative results,
- * we consider that a more approximate result is okay. In
particular it does not make sense to require a
- * 1E-7 accuracy (relative to cell size) if we don't
really know what the answer should be.
+ * consistency with forward transform. We relax the
threshold only if the result is apparently outside the
+ * grid (since there is no authoritative result outside
the grid, it does not make sense to require a 1E-7
+ * accuracy if we don't really know what the answer should
be). If we can not find an answer, we throw an
+ * exception even if the points seem outside since
experience shows that the point is not always outside;
+ * sometime the algorithm wrongly think that the point is
outside while it should actually have been inside.
*/
if (--it < 0) {
- if (it == -1) {
- if (forward.grid.isCellInGrid(xi, yi)) {
- throw new
TransformException(Resources.format(Resources.Keys.NoConvergence));
- }
+ if (it == -1 && !forward.grid.isCellInGrid(xi, yi)) {
tol = 0.5;
} else {
- xi = yi = Double.NaN;
- break;
+ throw new
TransformException(Resources.format(Resources.Keys.NoConvergence));
}
}
}
