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--- kvalobs:kvoss:system:qc2:requirements:algorithms:gapinterpolate [2011-09-01 21:47:37]
paule
+++ kvalobs:kvoss:system:qc2:requirements:algorithms:gapinterpolate [2022-05-31 09:29:32] (current)
@@ Line 1: / Line 1: @@
-====== GAP INTERPOLATION ======
-^ - ^Todo ^
-|  |  ... |
+Feedback on this page (LA):
+   * The size of gap is essential for allowing interpolation.
+   * The second derivative of the curve (f"(x)) the last 2-3 hours before the gap should influence on the size of an acceptable gap for interpolation; and also influence on whether to interpolate the first two hours of a larger gap or not. E.g.: If f"(x)>0 the last 2-3 hours before a 10 hours gap (graph 4),
+   * Skeptical concerning interpolation of the first two hours. But if the the gap is only 5 hours suggest to accept the interpolation.
+   * If f"(x) is changing sign the last hour before the gap (or second hour after the gap) suggest a two hours interpolation of a larger gap.
+   * Concerning flagging, the acceptable size of a gap will become important for using ftime=1 or ftime=2.
+====== GAP INTERPOLATION ======
 The Akima Spline interpolates based on the gradients between points of the nearest neighbours in the time series. At least five neighbours are required (this may be satisfied by having two to three points on either side of a gap). The values of more distant neighbours appear to have little effect on the finally interpolated data.
@@ Line 20: / Line 26: @@
 **Original Data**
-{{:kvoss:system:qc2:requirements:algorithms:original_data.png|}}
+{{kvalobs:kvoss:system:qc2:requirements:algorithms:original_data.png|}}
 **Simulated Gaps**
@@ Line 26: / Line 32: @@
 For this example we generate our own gaps so that the results may also be compared to the original values.
-{{:kvoss:system:qc2:requirements:algorithms:simulated_gaps.png|}}
+{{kvalobs:kvoss:system:qc2:requirements:algorithms:simulated_gaps.png|}}
 **Akima Fit**
-{{:kvoss:system:qc2:requirements:algorithms:akima_fit.png|}}
+{{kvalobs:kvoss:system:qc2:requirements:algorithms:akima_fit.png|}}
 **Akima Fit also indicating the interpolated data points (triangles) and original values (red circles)**
-{{:kvoss:system:qc2:requirements:algorithms:original_and_fit.png|}}
+{{kvalobs:kvoss:system:qc2:requirements:algorithms:original_and_fit.png|}}
 **Comparison of data**
@@ Line 54: / Line 60: @@
 The following sketch illustrates these points:
-{{:kvoss:system:qc2:requirements:algorithms:gapinterpolateideas.jpg|}}
+{{kvalobs:kvoss:system:qc2:requirements:algorithms:gapinterpolateideas.jpg|}}
 **Think Tank**