[Kst] [Bug 102898] New: modified netCDF datasource reader: problems with plots

Kimberly Scott kscott at nova.astro.umass.edu
Thu Mar 31 01:41:09 CEST 2005

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           Summary: modified netCDF datasource reader:  problems with plots
           Product: kst
           Version: unspecified
          Platform: unspecified
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
        AssignedTo: kst kde org
        ReportedBy: kscott nova astro umass edu

Version:           1.1.0 (using KDE KDE 3.3.2)

My modified version of the netCDF datasource reader is able to read netCDF files that have fields with multiple samples per frame, and it seems to be reading files just fine.  However, when we declare new vectors of our variables and try to plot curves, we do not see what we expect.

Considering just two of our variables, "sf" is a field with one sample per frame, while "mf" has 64 samples per frame.  sf is a counter, so it's vector values are like those for the "INDEX" field.  mf counts from 0 to 63 within each frame of sf.

I am trying to plot mf vs. sf.  In the "New Vector" window, I choose the field sf, set the "Range" to 100, and indicate to count from the end of the file.  The "Units" is set to frames, which seems to be the only option as of now.  I do the same for the field mf, again setting the "Range" to 100, as I am expecting Kst to read 100 frames of data for the mf variable (that is, 100 x 64 samples for mf).

When I plot mf vs. sf, I expect to see a "saw-tooth" pattern, with mf going from 0 to 63 within one frame of sf, dropping to zero at the start of the next frame of sf, and repeating this pattern 100 times.  Instead, I only see 100 samples for mf plotted, starting with the first sf value.  It seems that Kst is only plotting the first 100 samples for mf, not 100 frames.

I am unsure if this is an issue with our datasource reader, or with the way that Kst thinks about frames and samples.  The "Units" option in the "New Vector" window is set to frames, so I expect to be grabbing 100 frames of data, but it looks like for fields with multiple samples per frame, it only grabs 100 samples.  Do you know why Kst does this?

I am attaching copies of my modified code for the netCDF datasource reader, the .nc file I am using, and the .kst file of my sample plots.  The "h0b8" field has 64 samples per frame like mf.  The values of h0b8 are not important.

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