## SYNOPSIS

# A simple contour plot in black and white

use PDL::Graphics::TriD;

use PDL::Graphics::TriD::Contours;

$size = 25;

$x = (xvals zeroes $size,$size) / $size;

$y = (yvals zeroes $size,$size) / $size;

$z = (sin($x*6.3) * sin($y*6.3)) ** 3;

$data=new PDL::Graphics::TriD::Contours($z,

[$z->xvals/$size,$z->yvals/$size,0]);

PDL::Graphics::TriD::graph_object($data)

## FUNCTIONS

*new()*

Define a new contour plot for TriD.

$data=new PDL::Graphics::TriD::Contours($d,[$x,$y,$z],[$r,$g,$b],$options);

where `$d` is a 2D pdl of data to be contoured. [$x,$y,$z] define a 3D
map of `$d` into the visualization space [$r,$g,$b] is an optional [3,1]
piddle specifying the contour color and `$options` is a hash reference to
a list of options documented below. Contours can also be colored by
value using the set_color_table function.

ContourInt => 0.7 # explicitly set a contour interval ContourMin => 0.0 # explicitly set a contour minimum ContourMax => 10.0 # explicitly set a contour maximum ContourVals => $pdl # explicitly set all contour values Label => [1,5,$myfont] # see addlabels below Font => $font # explicitly set the font for contour labels If ContourVals is specified ContourInt, ContourMin, and ContourMax are ignored. If no options are specified, the algorthym tries to choose values based on the data supplied. Font can also be specified or overwritten by the addlabels() function below.

*addlabels()*

Add labels to a contour plot

$contour->addlabels($labelint,$segint,$font);

`$labelint` is the integer interval between labeled contours. If you
have 8 countour levels and specify `$labelint`=3 addlabels will attempt
to label the 1st, 4th, and 7th contours. `$labelint` defaults to 1.

`$segint` specifies the density of labels on a single contour
level. Each contour level consists of a number of connected
line segments, `$segint` defines how many of these segments get labels.
`$segint` defaults to 5, that is every fifth line segment will be labeled.

## set_colortable($table)

Sets contour level colors based on the color table.
`$table` is passed in as either a piddle of [3,n] colors, where n is the
number of contour levels, or as a reference to a function which
expects the number of contour levels as an argument and returns a
[3,n] piddle. It should be straight forward to use the
PDL::Graphics::LUT tables in a function which subsets the 256
colors supplied by the look up table into the number of colors needed
by Contours.

*coldhot_colortable()*

A simple colortable function for use with the set_colortable function.
coldhot_colortable defines a blue red spectrum of colors where the smallest contour value is blue, the highest is red and the others are shades in between.