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SEGYImport allows nonsensical values for margin

I have been playing around a bit with SEGYImport and observed the following behavior which does not really make sense to me. I wonder if one could check for such nonsensical values when using SEGYImport

Observations

  • I can specify negative margin sizes

    SEGYImport --lod-levels=0 --margin -1 volve.sgy --vdsfile=volve.vds

    The conversion will go up to 99.X % and then hang. I did not wait too long and aborted the conversion. The resulting file still looks somewhat reasonable and the header is intact, i.e., I can check the header with VDSInfo. The resulting file also looks reasonably large, but a bit smaller than for --margin 0. I did not try to run any actual operations (requesting data or similar) from the VDS dataset.

  • I can specify margins greater and equal to the brick size.

    SEGYImport --lod-levels=0 --margin 64 volve.sgy --vdsfile=volve.vds

    This returns really quickly without any error message. However, the resulting VDS dataset is only 2MB large. It seems that (only) the header is written (correctly), but no other content. It have not checked the generated VDS any further though.

    For margin sizes greater than the brick size, I wonder what the meaning would be. Should the margin contain container information of neighboring bricks and their neighbors?

  • I observe the behavior of generating VDS datasets of 2MB (point above) as soon as my margin is at least half the brick size. In this case 32.

It could be that some of the behavior is linked to the amount of memory (32GB) or storage (about 640 Gi available).

Platform

  • Apple Arm M1 Max
  • MacOS 13.1
  • OpenVDS 3.0.3 (compile from source)