AMOS TOME Series IV Manual  Index Prev Page Next Page 60

Map Set Zone zone,x1,y1 To x2,y2
This command works almost exactly the same as the Set Zone command, except that the x & y parameters are in tiles, and the zones apply to the map. The zone number can range from 1-the number of zones reserved.

=Map Zone(x,y)
This function returns a zero if the map co-ordinate x,y is not in a map zone, or the zone number that the coordinate is in.