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Point-Stat Tool: Output

The output of Point-Stat is one or more ASCII files containing statistics summarizing the verification performed. In this example, the output is written to the tutorial/out/point_stat directory as we requested on the command line. That output directory should now contain 5 ASCII files, one each for the CTC, CTS, CNT, and SL1L2 line types, and a fifth for the VSDB file. The VSDB file contains all of the output statistics while the other ASCII files contain the exact same data organized by line type.

Since the lines of data in these ASCII file are so long, we strongly recommend configuring your text editor to NOT use dynamic word wrapping. The files will be much easier to read that way.

Open up the tutorial/out/point_stat/point_stat_360000L_20070331_120000V_ctc.txt CTC file using the text editor of your choice and note the following:

• This is simple ASCII file consisting of several rows of data.
• Each row contains data for a single verification task.
• The FCST_LEAD and FCST_VALID columns indicate the timing information of the forecast field.
• The OBTYPE column indicates the observation type used for this verification task.
• The VX_MASK column indicates the masking region over which the statistics were accumulated.
• The TYPE column indicates the line type. In this file, it is of the form CTC followed by the threshold value applied to the field.
• The VAR column indicates the GRIB code abbreviation for the field being verified.
• The LEVEL column indicates the vertical level of the field being verified.
• After the = sign column, the CTC line type simply lists the counts for the contingency table computed by applying the threshold to the forecast/observation matched pairs. The FY_OY, FY_ON, FN_OY, and FN_ON columns indicate those counts.
• The INTERP_MTHD and INTERP_PNTS columns at the end of the line indicate the method used to interpolate the forecast data to the obseravation location.

Close that file, open up the tutorial/out/point_stat/point_stat_360000L_20070331_120000V_cts.txt CTS file, and note the following:

• The first 9 columns, up to the = sign, contain the same data as the previous file.
• The TYPE column is of the form CTS followed by the threshold value applied and the alpha value used in computing confidence intervals.
• The remaining columns contain statistics derived from the thresholded contingency table counts. See section 4.3.3 of the MET User's Guide for a thorough description of the output.
• Confidence intervals are given for each of these statistics, computed using either one or two methods. The columns ending in _NCL and _NCU give lower and upper confidence limits computed using assumptions of normality. The columns ending in _BCL and _BCU give lower and upper confidence limits computed using bootstrapping.

Close that file, open up the tutorial/out/point_stat/point_stat_360000L_20070331_120000V_cnt.txt CNT file, and note the following:

• The first 9 columns, up to the = sign, contain the same data as the previous file.
• The TYPE column is of the form CNT followed by the alpha value used in computing confidence intervals.
• The remaining columns contain continuous statistics derived from the raw forecast/observation pairs. See section 4.3.3 of the MET User's Guide for a thorough description of the output.
• Again, confidence intervals are given for each of these statistics as described above.

Close that file, open up the tutorial/out/point_stat/point_stat_360000L_20070331_120000V_sl1l2.txt SL1L2 partial sums file, and note the following:

• The first 9 columns, up to the = sign, contain the same data as the previous file.
• The TYPE column indicates the SL1L2 partial sum line type.

Lastly, the tutorial/out/point_stat/point_stat_360000L_20070331_120000V.vsdb VSDB file contains all of the same data we just viewed but in a single file. The VSDB-Analysis tool, which we'll use later in this tutorial, only reads the VSDB output of the Point-Stat and Grid-Stat tools, not the ASCII (.txt) files.