Graphing with Gnuplot and Xmgr

Once it is in an internal set, the data can be manipulated in many ways. Sets may be edited, deleted, and saved. Arbitrary mathematical functions can be typed in to transform one set to another. Regression, sometime referred to as “curve-fitting”, can be done on a variety of standard curves—polynomial, logarithmic and exponential. Histograms can be created from sets with user-definable bin widths. Many other mathematical operations are supported. Individual data sets (as well as complete graphs) can be saved and loaded.

Xmgr also allows the user to define “regions” entered as polygons determined by mouse clicks. Data points within a region can be extracted from data sets into other data sets or removed from data sets. The regression options may also be set to operate only on the inside or outside of a particular region.

Gnuplot has its own Usenet newsgroup, comp.graphics.gnuplot. The current version is 3.5. Gnuplot can be downloaded from Gnu ftp sites like prep.ai.mit.edu and its mirrors.

The gnuplot 3.5 distribution comes with a tutorial written in LaTeX. The regular gnuplot documentation can be compiled into several different formats, one of which is the on-line help file. Other formats are a VMS .hlp file, a TeX document, nroff/troff format and an .rtf rich-text format. A man page is also provided, which talks about invocation options and X-resources that are used.

The current version of xmgr is 3.01. Xmgr has a home page located at www.teleport.com/~pturner/acegr/index.html. FAQs, on-line documentation, source and binaries are there. Other pages still have some dangling pointers to the old xmgr home page at ogi.edu, where the mailing list is still hosted.