subgrider

Manipulations and statistics of grids in the GSLIB format

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subgrider is a tool to perform some simple manipulations, data extraction, and computation of some statistics, of data structured in the Geo-EAS format (a.k.a. GSLIB format). This is a regular grid in 3-D.

It was developed during the work for my MS thesis, entitled Applying Spatial Bootstrap and Bayesian Update in uncertainty assessment at oil reservoir appraisal stages (original title is in Portuguese), defended in Instituto Superior Técnico, December 2010, Lisbon, Portugal. The corresponding extended abstract (in English) is available in arXiv: arXiv:1702.04450. It had some further development in the following year, while I was working with integration of coarse and fine data (BGeost - Liu and Journel, 2009).

After all this time, I finally make it available here, mainly for educational purposes (maybe just for myself). The code is obviously poorly mainted, it only includes a simple text interface, which is in Portuguese, as well as the few comments in the code (eventually I may translate it to English). I cannot be held liable for any of its use or consequences of its use. It is released under GPLv3. I was not using git at the time, but I tried to to recreate some of the development history, including the binaries generated at that time.

I am happy to receive and reply to any issue on it.

Features

• Extract data

  • Vertical line, given coordinates (x, y)
  • Multiple vertical lines, given file with coordinates (x, y)
  • Subgrid, given a cuboid volume within the initial grid (subgrider!)

• Data manipulation

  • Create a mask (0 or 1)
  • Bend and unbend, given a map with the shifts
  • Upscale (create coarse data (blocks) in BGeost format)
  • Convert BGeost format to GSLIB point set

• Sampling

  • Random sampling of vertical line, given file with coordinates (x, y)

• Statistics

  • Mean and variance of simulated maps
    • Input - several grids with the same dimensions
    • Output - one grid with the same dimension which values are the mean or variance

• Bayesian update

  • Percentile
  • Quantile
  • Likelihood