             @features.push new google.maps.Polygon
                 paths: [new google.maps.LatLng(ll...) for ll in obj.coords[0]]
                 title: obj.name
-                strokeColor: @color
-                fillColor: @color
-                strokeOpacity: 0.1            if obj.weight?
-                fillOpacity: obj.weight / 100 if obj.weight?
+                strokeColor: if obj?.weight > 0 then @color else @neg_color
+                fillColor:   if obj?.weight > 0 then @color else @neg_color
+                strokeOpacity: 0.1                        if obj.weight?
+                fillOpacity:   Math.abs(obj.weight / 100) if obj.weight?
                 zIndex: if obj.weight? then 1 else 2
 
     load: (just_load=null) ->

map = null

class CustomOverlay
    constructor: (@json_script, @color) ->
        @features = []

    add: (obj) ->

    universities: new CustomOverlay('overlay.php?t=universities', '#009')

heatmaps =
    rates:        new CustomOverlay('overlay.php?t=sample_heat', '#0a0', '#aa0')
    rest_density: new CustomOverlay('overlay.php?t=rest_density', '#900')
    univ_density: new CustomOverlay('overlay.php?t=univ_density', '#00a')

