SNMAP plots sounding data on a map.


INPUT PARAMETERS
 
    AREA      *Data area
    GAREA     *Graphics area
    SNPARM    *Sounding parameter list
    DATTIM    *Date/time
    LEVELS    *Vertical levels
    VCOORD    *Vertical coordinate type
    SNFILE    *Sounding data file
    COLORS    *Color list
    MAP       *Map color/dash/width
    LATLON    *Line color/dash/width/label/inc
    MARKER    *Marker color/type/size/width/hw
    TITLE     *Title color/line/title
    CLEAR     *Clear screen flag
    PANEL     *Panel location/color/dash/width
    DEVICE    *Graphics device
    PROJ      *Map projection/angles/margins
    FILTER    *Filter data factor
    TEXT      *Text size/font/width/hw flag
 
 
PROGRAM DESCRIPTION
 
    SNMAP plots sounding data parameters at station locations
    on a map.  Any level or station parameter that can be
    computed can be displayed.

    The order of the input parameters determines their location
    on the plot.  Parameters are separated by semicolons.  A
    position may be skipped by entering two consecutive
    semicolons or entering parameter SPAC or BLNK.  A parameter
    will be plotted centered at the station if it is the first
    parameter in the list. If no parameter is to be displayed
    centered on the station location, a semicolon must appear
    before the first parameter, or the first parameter must be
    either SPAC or BLNK.  The following chart shows the placement
    of the data around the station.  The number indicates the
    position of the parameter in the SNPARM list:

				8
			2	10	4
			3	1	5
			6	11	7
				9


    Station data will be filtered; i.e., overlapping stations
    will not be plotted, if FILTER is set to YES.  FILTER may
    also be entered as a number greater than or equal to zero.
    FILTER = NO has the same effect as FILTER = 0.  FILTER = 1
    has the same effect as FILTER = YES.  Values less than 1
    allow more crowding of stations, values exceeding 1 less
    crowding.  If a parameter is BLNK, the filter will not allocate
    any space for that parameter.  The parameter SPAC may be used
    to reserve the space with the FILTER option so that later calls
    will plot the same stations after filtering, provided that the
    same number of parameters is specified.

    If certain stations are not to be removed by the filter, these
    stations are listed first following an @.  The area over which
    filtering is to occur is specified after a slash.  For example,

			AREA   = @iad;hts;rap/us
			FILTER = YES

    will display a filtered array of stations over the area
    corresponding to US, but IAD, HTS and RAP will be shown
    regardless of the filtering.

    Either wind barbs or wind arrows can be plotted, by
    specifying a wind symbol parameter name in the list of
    parameters for SNPARM.  The wind barb or arrow is plotted
    at the station location according to the type specification,
    which is entered as described in the SNPARM documentation.
    Any valid marker type may be plotted at the stations using
    MARKER.

    Conditions can be specified for the parameters.  The
    conditions are documented in the SNPARM documentation.  Note
    that individual parameters can be scaled using these
    conditional functions.  For example, TMPC*10 will plot
    temperature multiplied by 10.


EXAMPLES
 
    1.  Plot a polar stereographic map of stations in the Maryland
        area with temperature, dewpoint, and height in positions
        2, 3, and 4.  Plot the winds in knots using barbs.  Plot
        the data at 850 mb for the latest time in the file,
        MARCH.SND:

        AREA    =  md
        GAREA   =  md
        SNPARM  =  ;tmpc;dwpc;hght;brbk
        DATTIM  =  last
        LEVELS  =  850
        VCOORD  =  pres
        SNFILE  =  march.snd
        COLORS  =  2;3;4;6
        MAP     =  2
        LATLON  =
        MARKER  =  3
        TITLE   =  5
        CLEAR   =  yes
        PANEL   =  0
        DEVICE  =  xw
        PROJ    =  nps
        FILTER  =  no
        TEXT    =

    2.  Plot a Mercator map of the USA with the 500-mb temperatures
        to the left of the station and height to the right.  Plot
        the lifted index centered above the station in position 8.
        The data plotted is from February 12, 1985 at 1200 GMT.
        The plotting window will not be cleared prior to drawing
        the map.  No winds will be plotted.

        AREA    =  us
        GAREA   =  us
        SNPARM  =  ;;tmpc;;hght;;;lift
        DATTIM  =  850225/1200
        SNFILE  =  25feb12z.snd
        CLEAR   =  no
        PROJ    =  mer

    3.  The following specification for SNPARM will place the
        specified parameters in standard positions.

        SNPARM  =  brbk;tmpc;;hght;;dpdf


ERROR MESSAGES
 
    [SNMAP  +1]     Parameter ... cannot be computed.
    [SNMAP  -1]     Fatal error initializing TAE.
    [SNMAP  -2]     Fatal error reading TAE parameters.
    [SNMAP  -3]     Fatal error initializing GEMPLT.
    [SNMAP  -4]     Invalid levels or vertical coordinate have been input.
    [SNMAP  -5]     A range of levels is invalid in SNMAP.
    [SNMAP  -6]     Winds cannot be computed.