It was found to be necessary to convert the velocity model generation code to Python because:

• R code was using too much RAM.
• R code was slow.
• Using less RAM was taking too much effort and freeing RAM is slow.
• Looping over smaller subsets was too slow, difficult to work with.
• Everything is global, wasting RAM and messy.
• Libraries duplicating RAM of input data, not releasing it.
• Combining a 3GB dataframe after splitting it made it use 16GB RAM.
• Taking the first 20 million elements from a dataframe took ages and RAM usage blew up.

Outcomes

• Most if not all code runs in Python, mostly using numpy and gdal.
• Code runs in minutes instead of days.
• Can run on a machine with 32GB RAM (16GB should be enough too).
• Can run with larger input datasets.
• Can create finer resolutions than 100m.
• Results easily viewed/interrogated in QGIS project. Easily shared.

Currently all processing elements have had Python algorithms/process found/investigated except MVN.

Steps

• s65 Terrain model interpolation given values (core completed).
• s65/s66 Geology model polygon interpolation (algorithm found 10,000s times faster).
• s66 Rest of geology model datasets, eg store slope as TIFF.
• s66 Rest of geology model processing rules.
• s66 Synchronise outputs between geology and terrain (run with same parameters).
• s66 Combination of geology/terrain.
• s66 Store all outputs.
• s66 Argument version for running complete workflow.
• s66 Create QGIS project including outputs as layers, open street map.
• s66 Convert VSPR to Python (loading and pre-processing measured sites).
• s66 Posterior model modification to Python using already available clustering code.
• s66 Run at 50m, 10m resolution.
• s66 Compare results.
• s67 Look into converting MVN code to Python (find main algorithms/ processes required).
• s67 Convert if algorithms/processes found and reasonable in Python.
• s67 Implement MVN in Python.
• s67 Point based calculation as well as raster based.
• s67 Investigate sources of differences (Vs30 Data Reproducibility/Verification).