create layer with multiple categories and layering transparency

[deleted-user-ugCMpXci8bn5]

I am trying to make a 'faux' heat map, by using graduated symbols that also have some transparency, so that when they are layered (especially at small-scale views), the layering of the symbols gives a darkened color effect.

I can do this by creating a separate layer for every symbol category, but I would like to do this within a single layer, using categorized symbols (it is a point layer).  Is this possible? I have seen some ideas about setting transparency for different symbol levels using field calculator, but this still doesn't give the effect I am looking for when symbols within the same layer are stacked.

I hope I am explaining this well, thanks for any help!

[CPoynter]

Have you tried playing around with adding a 'transparency' field to your attributes, so that it can be applied within the symbology settings under 'Advanced'?

Regards,

Craig

[deleted-user-ugCMpXci8bn5]

Craig,I tried that, but I think that only works with polygon layers.  Even in that case, I am not sure if the transparency is maintained withinclasses in the same layer.

[deleted-user-ugCMpXci8bn5]

Thanks for the  ideas.  I am not sure if converting to a polygon is feasible, as this will be for over 60 maps which will be published as map services and will need to be very responsive in a web application to a (jqwidget) time slider, zoom/pan and toggle events.

I imagine the lack of transparency of classes within a layer is on purpose; I would guess most people would not want this functionality. 

I am not too sure about cross hatching the point either; I hope that the points will be very precise and tight when viewing the map at a close-up zoom level. There are a few thousand points in each map, all in a relatively small area (the five boroughs)

But I will look into the ideas here, thanks for input!

[CPoynter]

Could you give a representation of what you are trying to present. Might spark an idea or two.

I have something in mind, but need to see if it is on the right track.

Regards,

Craig