[texhax] How to add math text to existing ps figure file

[Olsen, Bill]

I would like some ideas for how to add text to postscript files that I am including in a LaTeX document.  
I want to use LaTeX to generate the text, so that the fonts and math symbols will match the rest of my document. 
I need to place the text at specific places in the figures, and in some cases I will need to place the text on a white background that covers part of the figure.  

My figures consist of schematic drawings with axes, lines, curves, etc., which need labels.  So far, I have made my own postscript files from my own reseach code (Fortran) which knows the physical problems being worked on.  Some of the figures I could re-build from scratch, and include placeholders in the ps output for text, but some of the figures are pretty old and I doubt that I could find the original code to re-created them - for those I would just like to edit the ps files from scratch.

I would also be interested in learning a drawing environment for relatively simple figures.

I don't know where to begin.
My thanks to anyone who can point me in a fruitful direction.

Bill Olsen