RegridDataPlane: Using Python Embedding

met_tool_wrapper/RegridDataPlane/RegridDataPlane_python _embedding.conf

Scientific Objective

None. Simply regridding data to match a desired grid domain for comparisons.

Datasets

Forecast: ASCII sample file

Location: All of the input data required for this use case can be found in the met_test sample data tarball. Click here to the METplus releases page and download sample data for the appropriate release: https://github.com/dtcenter/METplus/releases

This tarball should be unpacked into the directory that you will set the value of INPUT_BASE. See Running METplus section for more information.

METplus Components

This use case utilizes the METplus RegridDataPlane wrapper to generate a command to run the MET tool RegridDataPlane if all required files are found.

METplus Workflow

RegridDataPlane is the only tool called in this example. It processes a single run time, but the data does not contain any time information in the filename, so the run time is irrelevant.

This use case regrids data to another domain specified with REGRID_DATA_PLANE_VERIF_GRID. This is done so that forecast and observation comparisons are done on the same grid. Many MET comparison tools have regridding capabilities built in. However, if the same file is read for comparisons multiple times, it is redundant to regrid that file each time. Running RegridDataPlane allows you to regrid once and use the output in many comparisons/evaluations.

METplus Configuration

METplus first loads all of the configuration files found in parm/metplus_config, then it loads any configuration files passed to METplus via the command line with the -c option, i.e. -c parm/use_cases/met_tool_wrapper/RegridDataPlane/RegridDataPlane_python_embedding.conf

[config]
# List of applications to run
PROCESS_LIST = RegridDataPlane

# time looping - options are INIT, VALID, RETRO, and REALTIME
LOOP_BY = INIT

# Format of INIT_BEG and INT_END
INIT_TIME_FMT = %Y%m%d%H

# Start time for METplus run
INIT_BEG=2005080700

# End time for METplus run
INIT_END=2005080700

# Increment between METplus runs in seconds. Must be >= 60
INIT_INCREMENT=43200

# List of forecast leads to process
LEAD_SEQ = 3

# Options are times, processes
# times = run all items in the PROCESS_LIST for a single initialization
# time, then repeat until all times have been evaluated.
# processes = run each item in the PROCESS_LIST for all times
#   specified, then repeat for the next item in the PROCESS_LIST.
LOOP_ORDER = times

# run regrid_data_plane on observation data
OBS_REGRID_DATA_PLANE_RUN = True

# List of variables to compare
OBS_VAR1_NAME = {INPUT_BASE}/met_test/scripts/python/read_ascii_numpy.py {INPUT_BASE}/met_test/data/python/obs.txt OBS

OBS_REGRID_DATA_PLANE_VAR1_OUTPUT_FIELD_NAME = OBS

# If true, process each field individually and write a file for each
# If false, run once per run time passing in all fields specified
REGRID_DATA_PLANE_ONCE_PER_FIELD = True

# Name to identify model data in output
MODEL = FCST

# Name to identify observation data in output
OBTYPE = OBS

# Used by regrid_data_plane to remap data
REGRID_DATA_PLANE_VERIF_GRID = G130

# method to run regrid_data_plane, not setting this will default to NEAREST
REGRID_DATA_PLANE_METHOD = BUDGET

# regridding width used in regrid_data_plane, not setting this will default to 1
REGRID_DATA_PLANE_WIDTH = 2

[dir]
OBS_REGRID_DATA_PLANE_INPUT_DIR = 
OBS_REGRID_DATA_PLANE_OUTPUT_DIR = {OUTPUT_BASE}/met_tool_wrapper/RegridDataPlane/regrid_py

[filename_templates]
OBS_REGRID_DATA_PLANE_INPUT_TEMPLATE = PYTHON_NUMPY
OBS_REGRID_DATA_PLANE_OUTPUT_TEMPLATE = numpy_data.nc

MET Configuration

None. RegridDataPlane does not use configuration files.

Python Embedding

This use case calls a Python script to read the input data. The Python script is stored in the MET repository: /path/to/MET/installation/share/met/python/read_ascii_numpy.py

read_ascii_numpy.py

Running METplus

This use case can be run two ways:

1. Passing in RegridDataPlane_python_embedding.conf then a user-specific system configuration file:

   run_metplus.py -c /path/to/METplus/parm/use_cases/met_tool_wrapper/RegridDataPlane/RegridDataPlane_python_embedding.conf -c /path/to/user_system.conf
   

2. Modifying the configurations in parm/metplus_config, then passing in RegridDataPlane_python_embedding.conf:

   run_metplus.py -c /path/to/METplus/parm/use_cases/met_tool_wrapper/RegridDataPlane/RegridDataPlane_python_embedding.conf
   

The former method is recommended. Whether you add them to a user-specific configuration file or modify the metplus_config files, the following variables must be set correctly:

• INPUT_BASE - Path to directory where sample data tarballs are unpacked (See Datasets section to obtain tarballs). This is not required to run METplus, but it is required to run the examples in parm/use_cases

• OUTPUT_BASE - Path where METplus output will be written. This must be in a location where you have write permissions

• MET_INSTALL_DIR - Path to location where MET is installed locally

Example User Configuration File:

[dir]
INPUT_BASE = /path/to/sample/input/data
OUTPUT_BASE = /path/to/output/dir
MET_INSTALL_DIR = /path/to/met-X.Y

NOTE: All of these items must be found under the [dir] section.

Expected Output

A successful run will output the following both to the screen and to the logfile:

INFO: METplus has successfully finished running.

Refer to the value set for OUTPUT_BASE to find where the output data was generated. Output for this use case will be found in met_tool_wrapper/RegridDataPlane/regrid_py (relative to OUTPUT_BASE) and will contain the following file:

• numpy_data.nc

Keywords

Note

• RegridDataPlaneToolUseCase

• PythonEmbeddingFileUseCase

Navigate to the METplus Quick Search for Use Cases page to discover other similar use cases.

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