Vector Plotting

box                       -- draw a box on the plot
clear                     -- erase plot
create                    -- create a new vector
cursor                    -- get coords from cursor
grid                      -- plot cartesian grid
hist                      -- create histogram from a vector
labels                    -- define labels for plot
limits                    -- define plot limits
plot                      -- plot a pair of vectors
print                     -- write vectors to file
ps                        -- define labels for plot
set                       -- vector math
style                     -- set the style for graph plots
vectors                   -- list vectors
zplot                     -- plot scaled points

In addition to scalar variables, status can manipulate and display 1-D vector variables. Many of the commands which extract data from the photometry database place the data in vectors as well as plotting them. A vector can also be created based on a number sequence with the command create name Nelements start delta. The resulting vector has $Nelements$ entries, starting at a value of $start$ and running until $start + delta*Nelements$. If $delta$ is 0.0, all elements will have the value of $start$. A histogram of a vector may be made with the command hist, which creates a new vector containing the histogram of the first vector. The data range and bin size of the histogram are defined in same way as with create. This makes it easy to create the index vector that goes with a histogram vector:

hist y Ny 1 100 0.1
create dx 1 100 0.1

The above will create a histogram of y in Ny and the index in dx. Plotting this with plot dx Ny will show the histogram.

Vector math is performed with a command of the form set new = (expression). The expression is some math function employing vectors and scalars. A complete listing of the math operators available in set can be found in the help for set.

Once vectors are defined, they may be plotted. A pair of vectors can be plotted against each other if they have the same number of entries. The plotting is performed on the graphics window, Kapa. There are actually several graphics windows available to status, any of which may be used to plot at any time. Some of the more complex operations default to either graphics window 0 or 1, depending on the context. Except for those functions with a pre-defined window, all plotting functions apply to the current graphics window unless an option -n N is given to specify a different window. The plotting style is determined by the command style which can set the line width, the line type (solid, dashed, dotted, etc), the point type (box, cross, etc), the point size, the color, and whether a pair of vectors is plotted as a sequence of points, a set of connected lines, or a histogram. Some functions which make plots use their own styles, as discussed below. The function limits lets the user set the range of the plot axes, or check the current setting. The command plot will plot a pair of vectors on the current graphics window using the current plotting style for that window. The command zplot will plot a pair of vectors with the point size scaled by a third vector, with maximum and minimum point sizes representing specified values. The cursor command goes the other way: this command puts the Kapa window in cursor mode and waits for input from Kapa. The user can then type any alphanumeric key on the graphics windows and will be told both the pointer location (in the graphics coordinates) and will have the coordinates stored in status variables. For example, by typing ``1'' in the sky display window, the RA and DEC of the pointer are stored in the variables $R1 and $D1. This command can be used to let the user define locations or regions of interest on the Kapa window. (Future addition: button, which does the same with the mouse buttons).