The Davis Guide to Centering in Arcplot

There are two tricks that are useful for centering text or other features in
Arcplot:

1. Creating a center line first, then using it as a reference line.  Similar
to using a T-square and triangle in cartography is the use of a graphic
vertical or horizontal line on the screen.  To create such a line, use the
Arcplot LINE command and supply two xy coordinate pairs.  Let's say you want
to center text in the center of your page and your PAGESIZE is 12 12.  You
could first create a center line using 'LINE 6 0 6 12' to draw a vertical line
down the middle of the page.  Then after a 'MOVE *' to a point on the line,
your text could be centered on this line with 

TEXT 'Margravate of Azilia' LC

in which LC stands for "Lower Center", and places the text such that the lower
center point of the text string is positioned at the reference point specified
by the MOVE command.  CC (Center Center) and UC (Upper Center) also work.

You could then position other text along this line.  The only problem with
this is that you may end up with a vertical line in your map composition.  You
can simply MSEL and MDEL it, or create it before you open your composition.


2. Actually only a minor variation on the previous example, this method does
not employ a line but simply suggests that you specify page location with the
MOVE command, as illustrated by the following example:

MOVE 6.0 13.0
TEXT 'Margravate of Azilia' CC

Though requiring fewer steps than the first method, you might find it more
difficult to determine the MOVE location.  You could use MEASURE WHERE to
first find the location, for which you're only concerned with the Y value,
then do the above with the X value you already know and the Y value you've
determined.