Specifies the order in which to draw this item on the map.

By default, all nodes are drawn above all links. There are some situations where you might like to change this, for example if you use a NODE as a background image, and you want links to show in front of that image.

By default, all nodes have a Z coordinate of 600, and all links have 300. The map legend is at 1000, which cannot be changed (you can move everything else above it, if you like, of course). Items are drawn from lowest Z up to highest Z, so if you want a particular node to appear underneath the default links, you can use 'ZORDER 250' to do that.