Radar package

View tropical storm Gabrielle as viewed by Smart-R1 at Venice, Florida 14 September 2001. (4.8 MB animated gif)

The radar package displays radar data. Currently it only reads Sigmet raw product volumes, as described in IRIS/Open Programmers Manual, Version 7.16, April 2000.

Requirements:

• Tcl/Tk 8.2 available with most recent Linux distributions.
• TkGeoMap 1.6.5.1 or later
• Visky 1.3.1 or later
• TkRadar 1.0 or later

• Load - leads to a cascading menu of radar types. Selecting one produces a file selection dialog box for radar files of that type. File type is determined from a pattern in the file name. Files whose names do not match the pattern for the type are not displayed in the dialog.

  Currently, the only recognized type is Sigmet. Sigmet files are assumed to be those with ".raw" somewhere in the file name. A ".gz" or ".bz2" suffix is assumed to indicate a compressed file, in which case the appropriate decompression program is called automatically. All other information about the volume is taken from inside the file.

  Once a file is selected, the file contents are read into a volume which is subsequently referred to by a token of form name_YYYYMMDDHHMMSS, where name is the radar name, and YYYYMMDDHHMMSS is the year, month, day, hour, minute, and second of the volume start time. If successful, the volume token is added to the Display and Delete menus described below.

  The most recent directory to provide a volume is recorded in $HOME/.visky/Radar/Sigmet/initialdir to speed navigation on subsequent load requests. Deleting this file restores the default (Tk's current working directory).

  Once a volume is loaded, pressing the right arrow loads the next volume file in the volume's directory, if there is one. Pressing the left arrow loads the previous volume file. The file sequence is alpha-numeric. Therefore, file names should be created such that their alpha-numerical order matches their chronological order.

• Display - chooses which sweep to display from cascading menus which select sweep time and data type. Currently, only PPI (Plan Position Indicator) sweeps can be displayed. Once a sweep is displayed, the up and down arrows move to higher and lower tilt angles. The most recent data type used is recorded in $HOME/.visky/Radar/Sigmet/WDataType, and is used as the initial data type for subsequent volumes. Deleting this file restores the default behavior, which is to display the first data type found in the volume.
• Delete - removes a selected volume from the display and all associated internal data structures.
• Bin dot size - selects the dot size for the bins. If default, the dot size specified under the "Widget->Default dot size" menu is used.
• Max volumes sets the number of volumes which can be loaded using the right and left arrows. Once this limit is reached, the oldest volume is deleted before another is read, keeping a constant number of volumes in memory. This makes it possible to "walk" through a directory without running out of memory. The chosen number is kept in $HOME/.visky/Radar/MaxVols. Deleting this file restores the default - two volumes in memory. Note that this limit applies only to loads initiated with an arrow key. The limit can be exceeded with the Load menu.
• Colors sets parameters for the color legend at the bottom of the display area. Selecting a radar type and data type produces a dialog with a sample legend, minimum data value, maximum data value, and the number of intervals. If a bin has value binValue, it is put into color interval n according to the formula:

  Min + n * (Max - Min) / NIntvls < = binValue < Min + (n + 1) * (Max - Min) / NIntvls
      

  If the data type is currently on display, the display is updated. The color legend parameters are stored in $HOME/.visky/Radar/Sigmet/Colors.tcl for use in subsequent runs. Deleting this file restores the defaults in the scripts. It can also be edited to permanently change the default behavior.