This application is a 2D plotting program. (A program that is similar to this, but written in C++, is on the C++ page.) It reads data from a text file describing a 2D curve and draws it out. The center of view can be moved left, right, up and down. The view can also zoom in or out. The user may set the plot color, background color, axis and window color. Axes drawing is also a user selectable option. User option are stored as persistent defaults. At any time the user can save the current display to a PDF file.

http://www.surfnetusa.com/jimd/objectivec.html