GDPLOT draws contour lines through a gridded scalar field, and draws barbs or arrows for vector grids. It can present any number of time periods. It can also produce any number of contours or vectors on each frame. INPUT PARAMETERS GDFILE *Grid file GDATTIM *Grid date/time GLEVEL *!Grid level GVCORD *!Grid vertical coordinate PANEL *!Panel location/color/dash/width SKIP *!Skip factor SCALE *!Scaling factor GFUNC *!Grid function CTYPE *!Contour type: C/F CONTUR *!Contour attributes CINT *!Contour interval/min/max LINE *!Line color/type/width/label FINT *!Fill interval/min/max FLINE *!Fill colors HILO *!Color/sym/rng/rad/cnt/int? HLSYM *!HILO txt size/posn/font/wdth/hw CLRBAR *!Bar clr/ornt/anch/x;y/ln;wd/freq GVECT *!Grid vector function WIND *!Wind symbol/siz/wdth/typ/hdsz REFVEC *!Size;y-loc;x-loc TITLE *!Title color/line/title TEXT *Text size/font/width/hw flag CLEAR *Clear screen flag GAREA *Graphics area PROJ *Map projection/angles/margins MAP *Map color/dash/width LATLON *Line color/dash/width/label/inc DEVICE *Graphics device PROGRAM DESCRIPTION GDPLOT draws contour lines through a scalar grid computed using the GEMPAK grid diagnostic functions. Then it draws a vector grid using wind barbs or arrows. It can present any number of time periods. It can also produce any number of contours or vectors on each frame. Contours may be displayed as lines or as a color fill. If CTYPE is L (or 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 either F/L or F/C. The attributes of the contour lines, including the color, line type, line width, and label frequency are specified in LINE. The four attributes must be separated with slashes; semicolons separate the values for each attribute. If the line type is set to a single negative number, negative contour values will have the absolute value of the line type and positive values will be solid. If the label type is set to a single number, n, then every nth value will be labelled. The attributes of the color fill are specified in FLINE. FINT specifies the interval or levels for the color fill. The first color specified in FLINE fills values less than the first level; while the last color fills values greater than the last level. Hence, n levels require n+1 colors. A range of colors may be specified in either FLINE or LINE by specifying starting, ending and increment values in that order separated by dashes. If the increment is missing, a default of 1 is used. The variables CINT and FINT specify contour interval, minimum value, and maximum value separated with slashes. A scaling factor may be entered in SCALE. The data in the grid file will be multiplied by 10 ** SCALE. If no contour interval is entered, a default value which will generate 5 to 10 contour lines will be selected. The scaling will be done before the contour interval is computed. If M is entered in the wind symbol specification of WIND, winds will be displayed in m/s, unless the KNOTV operator has been specified in GVECT, in which case the winds will be displayed in knots. If K is entered in WIND, the wind is displayed in knots. For contours, SKIP specifies the number of grid points to skip in generating contours. For example, if SKIP = 1, every other point is used to generate the contours. For vectors, SKIP specifies the number of points to skip in both coordinate directions. For example, SKIP = /1 will display winds at every other grid point. SKIP = /0 displays winds at every grid point. The HILO and HLSYM parameters control marking and labeling the values of relative maxima and minima. CLRBAR specifies a color bar to describe color fill contours. A map, lat/lon grid, and title may also be included. GDATTIM may be specified with a single time or a series of times in the following forms: ALL FIRST LAST first-last time1;time2;time3;time4;... first-last-increment GFUNC may contain exclamation points to delimit any number of sets of contour specifications. GVECT may contain exclamation points to delimit any number of sets of vector plot specifications. GLEVEL, GVCORD, PANEL, SKIP, SCALE, GFUNC, CTYPE, CONTUR, CINT, TITLE, LINE, FINT, FLINE, GVECT, WIND, REFVEC, HILO, and HLSYM may contain exclamation points to delimit specifications for the plots specified in GFUNC and GVECT. If any parameter contains more specifications than the number of plots specified in GFUNC or GVECT, they will be ignored. Positions between exclamation points may be left blank. A trailing exclamation point will be treated as a blank. If there is no trailing exclamation point, the last specification will be repeated for subsequent plots. EXAMPLES The simple examples from GDWIND & GDCNTR can be executed by GDPLOT without modification. The following examples demonstrate the more advanced features of GDPLOT. 1. All of the plots specified in GDCNTR and GDWIND can be combined. The spaces are added between exclamation points for readability. GDATTIM = 910819/00f00;910819/00f24 GLEVEL = 850 GVCORD = pres GFUNC = temp !dwpt !div(obs)! GVECT = wnd !grad ( tmpc ) ! !kntv (wnd) GDFILE = GEMDATA:hrcbob.grd PROJ = mer GAREA = co LINE = 1/-3/1/2!2/-3/1/4 !2/1/7/1 CINT = 4 !5 !0 SCALE = ! !5 !/999 MAP = 1/10 LATLON = 1/10/1/1/5;5 TITLE = 0 DEVICE = xw PANEL = ul !ul !ur !ul CLEAR = yes TEXT = CTYPE = C !C !F/L FINT = FLINE = ! !3;7 WIND = bm1 !an7 ! !bk1 SKIP = /0 !/1 HILO = 1!4!2;27 HLSYM = 1 CLRBAR = ! !1 ! 2. All of the plots from GDCNTR and GDWIND can be combined onto separate panels, and may be displayed for all of the intervening time periods. GDATTIM = 910819/00f00-910819/00f24 GLEVEL = 850 GVCORD = pres GFUNC = temp !dwpt !div(obs)! GVECT = ! ! !wnd!grad (tmpc)!kntv (wnd) GDFILE = GEMDATA:hrcbob.grd PROJ = mer GAREA = co LINE = 1/-3/1/2!2/-3/1/4!2/1/7/1 CINT = 4 !5 !0 SCALE = ! !5 !/999!/5 !/999 MAP = 1/10 LATLON = 1/10/1/1/5;5 TITLE = 1//Temp!4//Dwpt!2//Div !1//Wnd!4//Grad!8//KntV DEVICE = xw PANEL = ul !ul !ur !b CLEAR = yes TEXT = CTYPE = C !C !F/L FINT = FLINE = ! !3;7 WIND = ! ! !bm1!an4 !bk8 SKIP = ! ! !0 !1 HILO = 1!4!2;27 HLSYM = 1 CLRBAR = ! !1 ! ERROR MESSAGES [GDPLOT +1] WARNING. There are no contour levels. [GDPLOT -1] Fatal error initializing TAE. [GDPLOT -2] Fatal error reading TAE parameters. [GDPLOT -3] Fatal error initializing GEMPLT. [GDPLOT -4] Grid requested is not available. [GDPLOT -5] Error setting grid navigation for file .... [GDPLOT -6] There are no grids in grid file.