sarproz-group

poor cohernce

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    • #3207
      antig
      Participant

      Hi,
      Is somthere ideas how calcultate APS in relativliy poor coherence. I calculated intefereogrmms and full coherence maps and APS GRAF show poor coherence between images. Coregistration wet well no additional warnings. First stack had warings, but I increased area and second time was good no warnings at all.
      Quiestion is at such Star graph is it possible get realaieble result?

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    • #3211
      periz
      Keymaster

      if you process your data with the STAR graph,
      you look for good and stable targets in time, which usually are also little affected by geometric decorrelation.
      You could be in an area with average little spatial coherence but with a few sparse stable targets (like sparse isolated houses in the countryside) and everything would work.
      so, when you process the STAR graph, you do not really look at the spatial coherence.
      However, if such analysis would fail, you should care about the spatial coherence. But you would not use a STAR graph.
      To have an idea of your area check the MST graph. However for the processing it is suggested to use a redundant graph (more connections).
      Finally, looking at those average numbers is useful but limited. You have to process a set of interferograms to see things better.
      To evaluate an area, always check: reflectivity map, amplitude stab. index and coherence built with MST
      best

    • #3213
      antig
      Participant

      I used Delunay connection graph and detected seasonal coherence loss. Does it mean that availibiltiy to get data is most worst intefereogram coherence?

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