Map Aesthetics provide users with many ways of customizing the look of generated displays. Here you can see how to control some of the common aspects of GEMPAK graphics.
Each of the parameters you select will be given a color corresponding this color list.
sfparm=tmpk;relh;wsym;dwpf colors=1;2;3;4
TMPK will be color 1 (vanilla), RELH will be color 2 (red), WSYM will be color 3 (green), DWPF will be color 4 (blue)
First-last-increment
colors=1-31-5
This would give colors 1-35 in increments of five (1,6,11,16,21,26,31)
Color-coding of any parameter may be done based on its own value or on the value of any other computable parameter. There is a one-to- one correspondence between the elements in the color list and the elements in the parameter list (e.g., SFPARM). To color-code any parameter, replace its corresponding color number in the COLORS list with the form:
(v1;v2;...;vN-1/c1;c2;...;cN/PARM/E) or
(v1-vN-1-vInc/c1-cN-cInc/PARM/E) or
a combination of a list and a range
where the v's are parameter values, the c's are color numbers, and
PARM is the parameter whose value determines the color. If PARM
is omitted, the parameter will be color-coded based on its own value.
The number of values must be one less than the number of colors. If
a value range is used, an increment must be specified. If a color
range is used and no increment is specified, 1 is assumed. For
example, to color-code a marker based on the 3-hour flash flood
guidance value, the color element corresponding to the parameter
MARK could be specified as:
COLORS = (0.5;1;1.5;2;3/2;19;21;22;6;4/FF03)
or
COLORS = (50;60;70;80/2;3;4;5;6/TMPF)
or
COLORS = (20-95-5/30-14//U)
meaning that values less than or equal to .5 inch would be plotted
with color 2, values greater than .5 but less than or equal to 1
would be plotted with color 19, etc.
The E is a flag to indicate whether to include the break value with
the lower range or the upper range of values. Valid values are L
and U, respectively. The default is L for inclusion in the lower
range of values. In the above example, the first data range is
X <= 0.5, the second is 0.5 < X <= 1.0, etc. If the U flag is added,
the ranges change to X < 0.5, 0.5 <= X < 1.0, etc.
blank defaults to color 1, 0=no map
0 or blank no lines
blank default to color 1, 0=no markers
NOTE: SFPARM provides for MARK which is embedded within the parameter listing, rather than as a separate variable. This allows the user to take advantage of the COLOR parameter to set the marker color based on data values. When using MARK in SFPARM, the information is entered as MARK:type:size:width. Note that wind symbols and markers are always plotted at the center of the station model.
0=no title, blank default title
0 single panel, no border
When several parameters are selected, the map becomes cluttered with data. GEMPAK's filter can leave out some informat ion so no data will overlap, and you can actually read the map.
filter=yes No data overlap (Not cluttered) filter=1 No data overlap (Not cluttered) filter=no All data plotted (Cluttered) filter=0 All data plotted (Cluttered)
You can choose a decimal
between 0 and 1 for a finer adjustment (0.7 is a good choice).
0 or blank default
Enhancement Tables
Enhancement tables are found under the directory $GEMTBL/luts
Several predefined color tables are provided with the GEMPAK, and can be used within GEMPAK programs by using the LUTFIL variable.
Additionally, the enhancement can be changed after a mapping program has been run with the look up table command at the program prompt, ie:
LUT enhancement.tbl
Where enhancement is the name of the file. The default enhancement used for each image type is defined in the file IMGTYP.TBL. To select a different default enhancement for a given satellite image, simply enter a new enhancement name under the DEFAULT LUT FILE column.
Adding New Enhancement Tables
If you want to add new enhancement tables of your own, be sure to follow the format of one of the existing files. Location of RGB values is dependent on column location. When new enhancements are created, you will need to add the name to the $GEMTBL/luts/enhance.tbl file. Note that the enhancement names must end with the .tbl extension.
Exercise: Plot an IR image from this morning for the continental United States with temperature (F) observations overlayed, colored according to value (see above).
Some notes: