This contains a number of programs and tools used to build the [NZGD2000 deformation model] (https://github.com/linz/nzgd2000-deformation-model). These are used to build the deformation model, see the deformation-files repository where the data and scripts used for building the model are held.

The main tools are:

• gridtool

  a C++ program for processing grids, including trimming smoothing, etc (see gridtool.help)

• okada

  a program (calc_okada) for calculating surface deformation from a rectangular fault model (see calc_okada.help)

• gns_velocity

  a Fortran program based on GNS code for evaluating the GNS binary velocity model format

Also some python scripts for compiling components. The most significant are:

• python/build_grids.py

  Complicated script to generate a set of nested grids to represent deformation caused by a geophysical dislocation model. Automatically handles nesting based on accuracy tolerances. (see build_grids.md)

• python/build_model_csv.py

  Builds the model.csv file in the deformation model based directory by interrogating the component.csv files in the component subdirectories

• python/buffer_land_extents.py

  Build a multipolygon defining the land extents of New Zealand, over which the deformation model patches are required to match the geophysical model (used by build_grids.py). Input is a shapefile of New Zealand island polygons

• python/buffer_wkt.py

  Similar to buffer_land_extents - used to buffer the plate boundary polygons used to construct the offshore national velocity model component.

• python/dump_shift.py

  Converts a reverse patch to ntv2 format using make_ntv2.py, and generates a set of test data at semi-randomly selected points to go with it.