ps.map questions

[karen Bryant x6541]

I would appreciate it if anyone can answer the following
questions on ps.map:

1. "where x y" can and cannot be specified for which main
    instructions?

2. What are the default horizontal and vertical locations
   for x and y of "where x y"?

3. There is a box around the map I created with ps.map,
   but I did not direct the creation of this box.  Where
   does the box come from?  How can I keep it from being
   created?

4. I was trying to use "header" to create a title for my
   map, and I wanted to center the title on the map.
   However, ps.map will not take "where x y" under the 
   instruction, "header".  Is there any way to specify
   the position for the header?

Thanks for any answers!

Karen Bryant