## DESCRIPTION

d.linegraph is a primitive program to draw simple x,y line graphs based on numerical data contained in separate files.

Data file format
The X and Y data files for the graph are essentially a column of numbers in each file, with one input number per line. The program expects that each X value will have a corresponding Y value, therefore the number of lines in each data input file should be the same. Essentially, the X data becomes the X axis reference to which the Y data is plotted as a line. Therefore, the X data should be a monotonically increasing progression of numbers (i.e. "1,2,3,..."; "0, 10, 100, 1000,..."; "...-5,-1,0,1,5..."). If multiple Y data files are used, the Y axis scale will be based on the range of minimum and maximum values from all Y files, then all Y data given will be graphed according to that Y scale. Therefore, if multiple Y data inputs are used with dissimilar units, the graph produced comparing the two will be deceptive.

directoryname
  Path to the directory where the input files are located.
  Example format: /usr/grass/data/graph
ycoloroption[,option,...]]
  Color to be used for drawing the lines in the graph. If multiple Y data files are used, an equal number of colors may be used to control the colors of the lines. Colors will be assigned to Y data in respect to the sequence of instantiation on the command line. Options are listed below. By default, a series of colors will be chosen by the program if none are provided upon invocation.
  Order of default colors: yellow, red, green, violet, blue, orange, gray, brown, magenta, white, indigo).
titlecoloroption
  The color to be used for titles, axis lines, tics, and scale numbers.
  Default: "white"
  Color options: red, orange, yellow, green, blue, indigo, violet, magenta, brown, gray, white, and black.
xtitlevalue
  Title to describe X data. Will be centered beneath the graph. Default is no title unless the need for a unit descriptor is computed by the program (i.e. X: title in hundreds). Also, see NOTES section (below) for a format caveat for multi-word titles.
ytitlevalue
  Title to describe Y data. Will be centered beneath the X data title. Default is no title unless the need for a unit descriptor is computed by the program (i.e. Y: ttiittllee in thousands). Also, see NOTES section (below) for a format caveat for multi-word titles. In the case of graphs with multiple lines, one may wish to use more specific title placement by using the d.text or v.label programs.
titlevalue
  Title to describe the graph. Will be centered over the top of graph. Default is no title. See NOTES section (below) for a format caveat for multi-word titles.

## NOTES

Since the command line parser is not amiable to multiple word inputs, to input titles of more than one word, use the underscore character ("") to represent spaces (" ").

Example: "titleCensusdata1990" would be printed over the graph as "Census data 1990".

The way the program locates and labels tic marks is less than perfect: 1) although distances between Y tics is proportional to the value, they are not proportional on the X axis; 2) decimal values between -1 and 1 can be printed on the X axis, but not on Y. (With respect to the later, the input for Y values can all be multiplied by a factor of 10 before graphing).

It might be easier to use a 3rd party tool such as xgraph or GNUplot instead of d.linegraph. . (You can make GNUplot output pretty by using its SVG or PostScript output driver and converting that back into a rasterized image in a paint program)

## SEE ALSO

d.frame, d.text, v.label

## AUTHOR

Chris Rewerts, Agricultural Engineering, Purdue University

Last changed: $Date: 2012-12-28 11:52:38 +0100 (Fri, 28 Dec 2012) $