Because none other I could find had the features I
needed for a project. In particular, no editor could
deal with polylines. In addition, no editor I found
could deal easily with different coordinate systems.
And finally, I didn't like the way editing worked with any
other editor.
EditPoly is developed on a RedHat Linux PC (x86) box
with the latest distribution. It should work on any
reasonably current linux PC box.
It requires the fltk and OpenGL libraries.
An OpenGL video card is highly recommended.