GDTSPDF draws contour or color fill of cumulative probability 
or probability density as a function of grid values and
forecast time at a selected point and level or layer.

INPUT PARAMETERS
 
    GPOINT  Grid point
    GDATTIM Grid date/time
    GVCORD  Grid vertical coordinate
    GLEVEL  Grid level
    GFUNC   Scalar grid
    GDFILE  Grid file
    PTYPE   Plot type/h:w ratio/margins
    PRBTYP  Probability type
    CTYPE   Contour type:  C/F
    TAXIS   Time1-time2-tinc;lbl;gln;tck
    YAXIS   Ystrt/ystop/yinc/lbl;gln;tck
    BORDER  Background color/type/width
    LINE    Color/type/width/label/smth/fltr/scflg
    CINT    Contour interval/min/max
    HILO    Color/symbol/rng/rad/cnt/intp
    HLSYM   HILO txt size/posn/font/wdth/hw
    FINT    Fill interval/min/max
    FLINE   Fill colors/fill types
    CLRBAR  Color/ornt/anch/x;y/ln;wd/freq|text_info
    TITLE   Title color/line/title
    CLEAR   Clear screen flag
    SCALE   Scalar scale / vector scale
    PANEL   Panel loc/color/dash/width/regn
    DEVICE  Device|name|x size;y size|color type
    TEXT    Size/fnt/wdth/brdr/N-rot/just/hw flg
    OUTPUT  Output device/filename
 


PROGRAM DESCRIPTION
 
    GDTSPDF displays contours or color fills of a time series of
    probabilty at a fixed point and level or layer.  The probability
    is computed from ensemble data.

    GDFILE must specify an ensemble entry, a list of members
    enclosed within curly brackets. 

    GPOINT specifies the location for the probability.  
    It may be entered as a latitude and longitude 
    separated with a semicolon, as a station character 
    identifier or station number, or as a set of x and 
    y grid points separated with a semicolon and preceded 
    with an @.  The location may also be selected 
    graphically by setting GPOINT using the CURSOR
    command.  The location of the time series is then 
    selected by clicking on a horizontal map in another 
    GEMPAK XW window.

    The probabilities are computed as a function of GFUNC
    values and forecast time, and plotted as contours or
    color fills depending on user input CTYPE. If CTYPE 
    is C, contour lines are drawn using input from CINT
    and LINE.  If CTYPE is F, filled contours are drawn using
    specifications from FINT and FLINE. Both contour lines and
    filled contours are drawn if CTYPE is F/C.  The GFUNC values
    are plotted along the veritcal axis(Y) and the forecast times
    are plotted along the horizontal axis(X).
 
    PRBTYP specifies the probability type. If it is 1, the
    cumulative probability will be computed and plotted.  If it
    is 2, the probability density will be plotted.  The default
    value is 1.

    The increment entered in the YAXIS parameter determines
    the discretization for displaying the cumulative probability
    and for computing the difference in the cumulative
    distribution for displaying the density function.  The
    beginning and ending values specified in the YAXIS
    parameter determine the range of values for which
    the cumulative probability or probability density is
    to be displayed.  The label frequency may be used to
    reduce the number of labeled tick marks when high
    resolution of the distribution requires a small increment.
    Default values are provided if not specified in YAXIS. 

    Please note that SKEWT is not valid in vertical coordinate
    system in this program.

 
EXAMPLES
 
    1.  Plot the probability density contours of temperature at
        IAD 500 mb level for f24-f60 forecast hours, based on NAM 
        model output at 00, 06, 12z.

	GPOINT   = iad
 	GDATTIM  = f24-f60
	GVCORD   = PRES
 	GLEVEL   = 500
	GFUNC    = TMPC
	GDFILE   = {nam|00, nam|06, nam|12}
 	PTYPE    = lin
 	PRBTYP   = 2
 	CTYPE    = c
 	TAXIS    =  
 	YAXIS    =  
 	BORDER   = 1
 	LINE     = 2/2/3/1
 	CINT     = 10
 	HILO     = 2;4
 	HLSYM    = 2;1/3/2//HW
 	FINT     = 1
 	FLINE    = 1-20
 	CLRBAR   = 1
 	TITLE    = 1
 	CLEAR    = YES
 	SCALE    = 2
 	PANEL    = 0
 	DEVICE   = xw
 	TEXT     = 1/21//hw
 	OUTPUT   = T


ERROR MESSAGES
 
    [GDTSPDF  -1]    Fatal error initializing TAE.
    [GDTSPDF  -2]    Fatal error reading TAE parameters.
    [GDTSPDF  -3]    Fatal error initializing GEMPLT.
    [GDTSPDF  -5]    Invalid input for GDFILE.
    [GDTSPDF  -7]    Invalid input for PTYPE. 
    [GDTSPDF -11]    Input for YAXIS is invalid.
    [GDTSPDF -14]    Input for GPOINT is invalid.