classes drawing order

[John Bolster]

Hi all,

I need to understand the sequence in which different elements are drawn onto
the map. I understand that layers are drawn from top to bottom in the
mapfile, so a feature in a later layer can overlap a feature in an earlier
layer, but within one layer, are the classes drawn top down, or as they are
encountered as mapserv goes through the shapefile?

It's looking like the classes are just drawn as they are encountered, and
this is producing my problem:

All my roads are drawn with a black circle symbol of, let's say, 5px, with a
white circle symbol of, let's say, 3px on top. That makes for a nice
outlined road. Let's say my highways are a black circle symbol of 11px with
a colored circle symbol on top of 9px. So the highways are colored and have
a black outline.

But where a road intersects with a highway, if the road gets drawn first
it's good because the highway is drawn over the top of it, but if the
highway gets drawn first a little of the white of the road (half a circle of
it) is drawn out into the intersection, over the top of the highway fill
color.

As it stands, the roads and the highways are both classes of the same layer.
How do you all overcome this?

Thanks,

John Bolster