kmsgrid

kmsgrid is a small utility that makes it easy to work with the various datum grid files made by KMS/DTU for the transformation library TrLib (KMSTrans).

Using kmsgrid

kmsgrid is both a Python module and a command line utility.

Command line

The kmsgrid command line utility comprises two sub-utilities: “info” and “translate”.

$ kmsgrid --help
usage: kmsgrid [-h] {translate,info,help} ...

Read binary grid files from trlib.

optional arguments:
  -h, --help            show this help message and exit

Subcommands:
  Valid subcommands

  {translate,info,help}
                        additional help

Info

The info sub-command is used for getting information about a grid. Information can be queried about a single point, or about the entire file.

$ kmsgrid info --help
usage: kmsgrid info [-h] [--datum] [--mode] [--point I J] grid

positional arguments:
  grid         Binary grid file.

optional arguments:
  -h, --help   show this help message and exit
  --point I J  Value(s) at a grid index (I,J). Prints values from all
               dimensions of the grid.

Get information about a 3D grid:

$ kmsgrid info nkgrf03vel.01
      filename:  nkgrf03vel.01
    dimensions:  3
        latmin:  53.0
        latmax:  73.0
        lonmin:  3.0
        lonmax:  40.0
   data[0].min:  -0.96
   data[0].max:  1.75
  data[0].mean:  0.204704
   data[1].min:  -1.65
   data[1].max:  0.86
  data[1].mean:  -0.194318
   data[2].min:  -0.72
   data[2].max:  9.97
  data[2].mean:  2.34521
          dlat:  0.0833333333333
          dlon:  0.166666666667
          nlat:  241
          nlon:  223
         datum:  ITRF19yy/20yy
          mode:  KMSGrid
     tabletype:  3D

Values in a single grid cell at index 55,12:

$ kmsgrid info Geoids2013\nkgrf03vel.01 --point 55 12
0.649999976158 -0.200000002980 -0.720000028610

Translate

The translate sub-command work similar to gdal_translate in that it translates from one format to another. In fact, behind the scenes, it uses GDAL to convert KMS grids to more common formats. Only a small subset of the GDAL formats available can be used with kmsgrid.

$ kmsgrid translate --help
usage: kmsgrid translate [-h] [--driver DRIVER]
                         [--creation_options CREATION_OPTIONS]
                         grid out dimensions [dimensions ...]

positional arguments:
  grid                  Binary grid file.
  out                   Name of output grid file
  dimensions            List of dimensions in output grid, e.g. "1 2"

optional arguments:
  -h, --help            show this help message and exit
  --driver DRIVER, -d DRIVER
                        Output format. Currently supports: GTiff, GTX, NTv2
  --creation_options CREATION_OPTIONS, -co CREATION_OPTIONS
                        Additional GDAL creation options. Must be formatted
                        as "PARAM1=foo PARAM2=bar".

Translate the DVR90 geoid grid to GTX format:

$ kmsgrid translate --driver=GTX dvr90g2013.01 dvr90.gtx 1

Translate the NKG velocity model to two grids, one for the horizontal part in NTv2 format and one for the vertical part in GTX format:

$ kmsgrid translate –driver=NTv2 nkgrf03vel.01 nkgrf03vel_xy.gsb 1 2 $ kmsgrid translate –driver=GTX nkgrf03vel.01 nkgrf03vel_z.gtx 3

API

This is just a simple example of how the API can be used:

from kmsgrid import KMSGrid

# print some useful info
grid = KMSGrid('dvr90g.2013.01')
print('Dimensions of grid: {0}'.format(grid.dims))
print('Datum of grid: {0}'.format(grid.datum))
print('Bounding boix of grid: [{0}, {1}, {2}, {3}'.format(
    grid.lonmix, grid.latmin, grid.lonmax, grid.latmax))

# convert grid to a TIFF file
grid.export(filename='dvr90.tif', dimensions=1)

Installing

Clone the repository from GitHub and run the following command in the local repository folder:

$ python setup.py install

Alternatively kmsgrid can be installed from the Python Package Index with pip:

pip install kmsgrid

Release files for kmsgrid 1.1.0

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Built distribution (wheel)

Table of built distributions (wheels) for kmsgrid 1.1.0
File	Interpreter	ABI	Platform	Reset
kmsgrid-1.1.0-py2.py3-none-any.whl 10.3 kB Oct 18, 2017	Python 3, Python 2	none	any	Details

Release files / kmsgrid-1.1.0-py2.py3-none-any.whl

Download URL	kmsgrid-1.1.0-py2.py3-none-any.whl
Size	10.3 kB
Tags	Python 2 Python 3
SHA-256 checksum How to use checksums	`c1eec7e6ff1a7825b58938e13ed8bdf426d1521485dc1c9401907fdd38ef183e`
BLAKE2b-256 checksum How to use checksums	`9ff819f2cc8c67ca0ada31ea6934c2ecd838e070e0c98c4c15a977f4f83e92dd`
Upload date	Oct 18, 2017
Uploaded using Trusted Publishing? What is trusted publishing?	No