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equinor / seismic-zfp

Compress and decompress seismic data
GNU Lesser General Public License v3.0
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seismic-zfp 0.3.1 #81

Closed VitaminORA closed 1 year ago

VitaminORA commented 1 year ago

Dear all, I've tryed to use seismic-zfp, version 0.3.1. Firstly I've counted hash SGY file (metod SHA-1). 928D578CE3E0EC6BDE8896872EB7431584F5877D I've made compress SGY file and uncompress. In the end I've counted hash SGY file after uncompress (metod SHA-1)) E64792B077C6CFC9CB5392C805C95E98803085FB Files are different ???? Why ???? I used commands seismic-zfp sgy2sgz c:\Python\00\rr12.sgy c:\Python\00\rr12.sgz --bits-per-voxel 4 seismic-zfp sgz2sgy c:\Python\00\rr12.sgz c:\Python\00\rr12_sgz.sgy

da-wad commented 1 year ago

Because ZFP is lossy compression.

Lossless compression is not supported by seismic-zfp, but it's likely your workflow will work absolutely fine with lossy compression. Do a numerical comparison of rr12.sgy and rr12_sgz.sgy, and you should find the differences are very small in comparison to the absolute values. If you find there are many large differences please open a new issue.

VitaminORA commented 1 year ago

Thank you so much for answer