[OpenLayers-Users] Symbology

[Brad Bordine]

I am trying to use the dot density library from the openlayers symbology 
but I am running up against the reality that I do not understand how to 
call vector features properly. The postgres-served shape file I am 
calling has zip code geometry as well as numerous data cells, of which I 
need to access only one. I have looked at as many vector tutorials as I 
can find but nothing has made it easier for me to create a vector layer 
with all zipcodes and associated table rows. Obviously that is because I 
do not understand how to call the "features" from the data rows or the 
"features" which are the polygon objects... here is my call as it stands 
at the moment. I just tried adding an empty features set for fun, the 
same code failed without that line... Thanks in advance.

var zipPen = new OpenLayers.Layer.Vector("ZipPen", {
                 strategies: [new OpenLayers.Strategy.BBOX(bbox)],
                 protocol: new OpenLayers.Protocol.WFS({
                     version: "1.1.0",
                     url: "/geoserver/wfs",
                     featureType: "SPOOL_ZIP_July_1_13_test",
                     geometryName: "the_geom",
                     geometryType: "Polygon",
                     featureNS: "maps.decapower.org/Spool",
                     features: [],
                     srsName: "EPSG:4236"
                 })});

map.addLayer(zipPen);

var zipDensityLayer = new ol.thematic.DotDensity( map, {
                     layer     : 'ZipPen',
                     indicator     : 'NMPLTXZ_1',
                     dotValue    : 25,
                     defaultSymbolizer : { 'pointRadius' : 1, 
'fillOpacity' : 1, 'fillColor' : '#ffffff', 'strokeWidth' : 0 }
                     });