[mapserver-users] Point label collisions?

[Stephen Lime]

Point labels are subject to the same collision avoidance as other layers. That said there
are some special things going on that I don't know if they still make sense. Let me try
to explain...

My assumption is that with POINT layers that the points (i.e. symbols) themselves are very 
important and every effort should be made not to obscure them. With POINT layers all
points are drawn regardless of overlap and then labels are added. The current rule is that
labels can't overlap with each other, nor can they obscure another point. In crowded 
situations I could see where very few points would get labeled. The alternative would be
to allow label/symbol overlap but in testing that results very confusing output since you
could label something that itself becomes obscured by another label. The old earthquake
mapper I did showed this problem nicely. That's what I implemented the current rule.

Reading your message closely you might mean can symbols be shown without overlap?
At the moment, no, unless you turn your symbols into labels. Features are always drawn where
they are supposed to be drawn. Doesn't mean it couldn't be added though. It would mean 
adding a marker caching system which wouldn't be trivial but since there's already a label
caching system it wouldn't be that hard.

Steve

Stephen Lime
Internet Applications Analyst

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> "Mike Neuman" <mcn at engarde.com> 07/21/01 07:38PM >>>
  I know the mapserver is pretty smart about moving text labels around to
avoid overlaps, but can something similar be done with the point labels? In
other words, if I have 5 points in a little area, can it show them without
overlap?

  Thanks!

-Mike