Graphite Goals and Status

Graphite uses an object-oriented design which allows new plot types (i.e. PlotFormats) to be added easily. As a result, it is expected that the types of plots available will continue to grow. At a mininum, we expect to implement at least the following types:

• [Point Plot]A combination of scatter and line plot; each point in the dataset is plotted with a certain symbol, and connected to its neighbor with lines. The line may be omitted to obtain a traditional scatter plot; the symbols may also be omitted if lines are drawn. Optional error bars are available on all three axes; these may be specified asymmetrically or symmetrically. Line style and symbol style are configurable. Points may also be individually labelled. Lines may optionally be given a fill style, used to fill below the line, and a Z-thickness used in 3D plots.
• [Bar Plot]Each point is represented as a bar; the Y value indicates the height of the bar, and the X and Z specify bar position. Bar style (color, hashing, width, etc.) are configurable. Graphs containing multiple bar plots combine their displays in one of several ways: by displaying bars side-by-side, by stacking, or by overlaying. Bars may be individually labelled at the top. Labels below the bars may be specified as tick mark labels, as with any other plot type. Possibly, one may also give a set of labels as the X coordinate data (but this notion is not fully worked out yet).
• [Polar Plot]Each Y value specifies the radius of the data point and each X value specifies the angle.
• [Pie Plot]Each Y value specifies the angular extent of a slice of the pie; Z values, if given, are used to ``explode'' a slice out from the center. Each slice may be individually styled and labelled. The pie plot also has global attributes specifying its position and extent, making it easy to put several pies into one chart.
• [Density Plot]Requires three-dimensional data (e.g., Y as a function of X and Z). This plot is given a plane (defaulting to Z=0) on which to draw, and a palette function (several standard palettes will be provided); each point on the plane will be colored according to the corresponding Y value in the data. Additionally, isocontours can be located in the data and added to the plot.
• [Surface Plot]Similar to a Density plot, except that the surface drawn is extended into the third dimension rather than being confined to a plane. The surface is drawn with hidden line removal (unless the fill style is transparent), and with optional lighting. The user may also specify a color function to be applied to each point in the surface, e.g., color as a function of Y. One may also add either a mesh (periodic grid lines which follow the surface) to enhance perception of the surface, or contour lines. The camera position and projection time (perspective or orthographic) are adjustable - true with any plot, but especially relevant to the Surface plot. We hope to also add support for surfaces defined by irregularly sampled points.
• [Image Plot]Also similar to a Density plot, but more efficient at displaying large matrices of color values.

At the time of this writing only the Point Plot and Bar Plot graph types are implemented.