Plot-Point-Obs

Plot-Point-Obs griggs Wed, 04/24/2019 - 15:53

Plot-Point-Obs Functionality

The Plot-Point-Obs tool can be used to create a plot showing the locations of the point observations contained in the NetCDF output of the ASCII2NC, PB2NC, MADIS2NC, or LIDAR2NC tools. Occasionally, a postprocessing or timing error can lead to errors in MET. This tool can assist the user by showing the data to be verified to ensure that times and locations match up as expected.

Plot-Point-Obs Usage

View the usage statement for Plot-Point-Obs by simply typing the following:

plot_point_obs

At a minimum, the name of the file to be plotted, nc_file, and the output PostScript file, ps_file, must be passed in on the command line. The Plot-Point-Obs tool has command line options for filtering which observations get plotted and the area to be plotted. You may use the -data_file command line argument to specify a data file whose grid should be used for the plot.

Run

Run griggs Wed, 04/24/2019 - 15:54

Run Plot-Point-Obs to plot the output from PB2NC on the command line using the following command:

plot_point_obs \
$MET_TUTORIAL_DATA/output/pb2nc/tutorial_pb.nc \
$MET_TUTORIAL_DATA/output/plot_point_obs/tutorial_pb.ps

Next try rerunning Plot-Point-Obs using the -data_file option to plot the points using a different grid:

plot_point_obs \
$MET_TUTORIAL_DATA/output/pb2nc/tutorial_pb.nc \
$MET_TUTORIAL_DATA/output/plot_point_obs/tutorial_pb_zoom.ps \
-data_file $MET_TUTORIAL_DATA/input/sample_fcst/2007033000/nam.t00z.awip1236.tm00.20070330.grb

Output

Output griggs Wed, 04/24/2019 - 15:56

Display the first output PostScript file by running the following command:

gv $MET_TUTORIAL_DATA/output/plot_point_obs/tutorial_pb.ps &

Each red dot in the plot represents the location of at least one observation value.

Next display the output PostScript file that used a different grid by running the following command:

gv $MET_TUTORIAL_DATA/output/plot_point_obs/tutorial_pb_zoom.ps &

The plot_point_obs is useful in determining how many observation points actually fall within your verification domain.

The -gc and -msg_typ options may be used to further refine the observations to be plotted.
For example, -gc 11 -msg_typ ADPSFC plots surface observations of temperature (GRIB code 11).