Domain set of pixels to use. Scan pixel tabulation based on geometry. Display window on screen showing image. Overlay graphic to superimpose on an image. Objects can be saved, edited, shared among users.
Objects retain links to the objects to which they apply and from which they are derived.
We hope to adapt Tcl or another scripting language to this purpose. Objects represented by windows and icons. Operations selected from menus. Design by iteration and experimentation. Java makes this easy.