The MTD output typically consists of six files: five ASCII statistics files and one NetCDF object file. MTD does not create any graphical output. In this example, the output is written to the $MET_TUTORIAL_DATA/output/mtd directory as we requested on the command line.
The MTD output file naming convention begins with mtd_ followed by the last valid time it encountered. The output file names may be modified using the output_prefix option in the configuration file which should be used to prevent the output of one run from over-writing the output of a previous run. The six MTD output files are described briefly below:
- The NetCDF object file ends in .nc and contains gridded fields of the raw data, simple object indices, and cluster object indices for each forecast and observed timestep.
- The ASCII file ending with _2d.txt contains many columns similar to the output of MODE. This data summarizes the 2-dimensional object attributes for each individual time slice of the 3D forecast and observation objects.
- The ASCII files ending with _3d_single_simple.txt and _3d_simple_cluster.txt contain 3D space-time attributes for simple and cluster objects, respectively.
- The ASCII files ending with 3d_pair_simple.txt and _3d_pair_cluster.txt contain 3D space-time attributes for pairs of simple and cluster objects, respectively.
Use the ncview utility (if available on your machine) to view the NetCDF object output of MTD:
Select the variable named fcst_raw and click the time index to advance through the timesteps. Now, do the same for the fcst_object_id variable. Notice that the objects are defined in the active areas in the raw fields. Also notice some features merging (i.e. combining) as time passes while other features split (i.e. break apart). While they may be disconnected at a particular timestep, they remain part of the same space-time object.
Next, explore the ASCII output files and pay close attention to the header columns. Notice the generalization of the 2D MODE object attributes to 3 dimensions. Area meausure become volume. MTD measure the object speed. Each object has a beginning and ending time.
