liambindle/gridspec repository overview

⁠gridspec

Gridspec is a proposed standard for representing Earth system model grids. The standard was originally proposed by V. Balaji and Z. Liang (2007; reference⁠).

Gridspec files are useful for offline regridding with the Earth System Modeling Framework (ESMF⁠), but there are no generalized frameworks or utilities for creating gridspec files and data. This project aims to develop common tools for working with gridspec files and data.

⁠Supported grids

The grids that are currently implemented are:

• gnomonic cubed-sphere (see: gridspec-create gcs --help)
• stretched gnomonic cubed-sphere (see: gridspec-create sgcs --help)
• regular lat-lon grid (see: gridspec-create latlon --help)

See "Contributing" for information on submitting pull-requests and setting up a development copy.

⁠Compliance

• ESMF GRIDSPEC (subset of the standard)
• Full gridspec standard

⁠Installation

You can install gridspec like so:

$ pip install git+https://github.com/LiamBindle/gridspec.git 

This installs (see --help for subcommands and their usage):

• gridspec-create: create a gridspec file for one of the supported grids (mosaic or tile)
• gridspec-dump: displays useful information about a gridspec file
• gridspec-utils: utilities for working with gridspec data (splitting stacked data files, joining tiled data files, etc.)

⁠Examples

Creating a cubed-sphere grid:

$ gridspec-create gcs 24
Creating gnomonic cubed-sphere grid.
  Cubed-sphere size: C24

Writing mosaic and tile files
  + c24_gridspec.nc
  + c24.tile1.nc
  + c24.tile2.nc
  + c24.tile3.nc
  + c24.tile4.nc
  + c24.tile5.nc
  + c24.tile6.nc

Created 7 files.
$ 

Creating a stretched cubed-sphere grid:

$ gridspec-create gcs 24 -s 2 -t 40 -100
Creating stretched gnomonic cubed-sphere grid.
  Cubed-sphere size: C12
  Stretch factor:    2.0
  Target point:      40.0°N, -100.0°E

Writing mosaic and tile files.
  + c12_s2d00_t9z0gs3y0zh7w_gridspec.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile1.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile2.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile3.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile4.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile5.nc
  + c12_s2d00_t9z0gs3y0zh7w.tile6.nc

Created 7 files.
$ 

View the contents of a mosaic or tile file:

$ gridspec-dump c24_gridspec.nc                  
Gridspec mosaic  (c24_gridspec, 6 tiles, 12 contacts)
Tile files:      "c24.tile1.nc", "c24.tile2.nc", "c24.tile3.nc", "c24.tile4.nc",
...              "c24.tile5.nc", "c24.tile6.nc"

Gridspec tiles:
  tile1       (49x49)      logical center (  0.0°N, 350.0°E)    approx area: 8.5e+07 km+2
  tile2       (49x49)      logical center (  0.0°N,  80.0°E)    approx area: 8.5e+07 km+2
  tile3       (49x49)      logical center ( 90.0°N, 350.0°E)    approx area: 8.5e+07 km+2
  tile4       (49x49)      logical center (  0.0°N, 170.0°E)    approx area: 8.5e+07 km+2
  tile5       (49x49)      logical center (  0.0°N, 260.0°E)    approx area: 8.5e+07 km+2
  tile6       (49x49)      logical center (-90.0°N,  35.0°E)    approx area: 8.5e+07 km+2
$ 

⁠Contributing

Submit pull requests to https://github.com/LiamBindle/gridspec⁠. Please make sure to include tests for your PR.

To set up a developement copy:

1. Clone the repo

   $ git clone https://github.com/LiamBindle/gridspec
   

   Copy
2. Install as an editable package:

   $ pip install -e gridspec/
   

   Copy

⁠Tests

To run the tests, you need to install pytest⁠. Once pytest is installed, you can run the tests like so (pytest test discovery is described here⁠):

$ pytest