IPLOT is a (relatively) simple X,Y interactive plotting routine. It uses the PGPLOT plotting package, and thus allows the user to choose the output device for the plots; GraphOn terminal, X-window terminal, Post Script file, etc. In addition to the straightforward X,Y plotting mode of IPLOT, it also includes options which allow the user to

+ graphically trim the input data,
+ display information on individual data points,
+ operate on the input data to create new data,
+ generate functions y=f(x) using a built-in function parser,
+ perform least squares fits of polynomials to the data,
+ output modified data sets,
+ internally store a number of plotting data sets for retrieval,
+ add text to the plots
+ save the plot as an external *.iplot file


Local Access:


The program is controlled using single-character commands (occasionally, two-characters) selected from a menu line of options. The main menu contains:

New_data, Device, Axes, Symbol, Plot, X-hair, Fit, Trim, More, Etc, *, Quit
Some of these items contain sub-menus. The skeletal menu structure is given below. The functions of the main menu items are described on the following page.
New_data: >> New_file, Modify, Gen_x, X-hair
X-hair: >> Zoom, Coords, Find_pt, Del_pt
Fit: >> Order, Smooth, Bin_x, Ave_y, Med_y, Poly_fit, Resid, Integ, Deriv
Trim: >> Id_keep, Box_cut, Geo_cut, Del_pt
More: >> Store, Recall, Merge, Clear, Output, Link
Etc: >> Switches, Line_attrib, Char_attrib, Default, Text, Params
*: >> Write_file, Read_file, Viewport, Color
Hints and "Hidden" features:

Sample plots:



Give the program a try. And let me know of any bugs you find or of any other features/capabilities you would like to see added.

- Terry Girard


IPLOT Menu Description

New_data: Default mode asks for an input data file which can be read in using free format. (Fixed format is an option.) Data 'vectors' are stored in (up to) five arrays referred to as x, y, z, u, and v. (An integer id array can also be stored.)
Device: Allows the user to select the output device for the plot. Subframes on the output page can be specified.
Axes: The user specifies which data array (x, y, z, u, or v) is to be plotted along which axis, (X or Y), or used as error bars, (EX or EY), or as vectors, (DX and DY). Also, a character string can be assigned to each array and is used as an axis label when that array is plotted.
Symbol: A choice of plotting symbols is given. As is the option to connect the data points with a line. (See Appendix 2.) Color and variable symbol sizes are now also available.
Plot: Causes the data selected in Axes: to be plotted, using Automatic or User-specified scaling. Or the new data can be plotted on top of an existing plot. Inverted axes and "square" scaling (i.e. forcing the absolute scale in X and Y to match) are options.
X-Hair: The cross-hair cursor can be used to 1) zoom the plot in or out, 2) select data points for display of information or deletion, or 3) simply to read off the cursor coordinates.
Fit: A least squares fit using a polynomial of degree N is made to the current X,Y data. The residuals between the fit and data can be stored for subsequent plotting. In addition, function "massaging" can also be performed, such as 3-pt smoothing, binning, averaging, etc.
Trim: The cursor is used to draw a box, or general polygon, around the data points to be deleted or saved.
More: The working arrays (x, y, z, u, v) can be stored and recalled in internal buffers, or written to an output file. Also, multiple data sets can be linked together into one plot. In addition, stored buffer arrays can now be "merged".
Etc: Various plotting parameters can be set, such as character size and font, and line style and thickness. Also, text can be added to the plot.
*: Plots can be saved, (data, buffers, symbols, text, etc.), in an IPLOT format ascii file. Also, viewport and color maps can be defined in this menu.
Quit: To exit the program.