Resource: con_base
| Resource | con_base |
|---|---|
| Overview | Specifies the base value for color fill contours, and wind speed per grid distance. |
| Command Line | -cb=value |
| Environment Variable | wxpconbase |
| Possible Values | |
| Default Value | lowest contour value, max wind speed or 0 depending on application |
This resource is used to specify the contour base value. This has several applications depending on the application.
Value Ranging
Value ranging is the method of specifying what range of values to actually contour. This is specified with the con_base resource with the following syntaxes:
- >min - this specifies the minimum valid value to contour/color. This also sets the contour base value (see below).
- <max - this specifies the maximum valid value to contour/color
For example, if the wind speeds above 100 knots are to be shown, use:
upaplot -va=spd[knt] -cb=>100
Both a minimum and maximum can be specified if separated by commas.
Color Fill Contouring
When contouring a grid, the first color in the color fill array is linked to the lowest value range in the grid. Since the minimum value will change from plot to plot, the colors in the color fill will switch the values they represent. The con_base resource locks a particular value to the lowest color range. For example:
sfcplot -ci=2 -cb=0
will lock magenta into the range of 0-2 and light magenta to 2-4 and so on. These color ranges will not shift from plot to plot.
Negative Dash Line Contouring
When a negative dash line contour type is used, the breakoff point between line contours and the dashed contours is 0. Line contours exist at this value and above. Dashed contours appear below this value. The con_base resource is used to set the break point if it is not 0.
Data Plotting
When a contour interval is specified during data plotting, the plotted data will be colored based on the value. The minimum value for which the colors in the fill attribute arrays are linked to is 0 or the value of the con_base resource.
Last updated January 2014