The original idea for having the Content property on ARItem would be to allow you to put whatever you want to represent the item. It could be an Image, or a Drawing or whatever. The probelm I ran into with that approach was that I found I really wanted a different appearance for the item in the different views. e.g. the item should look different in WorldView (3D) than it does in the overhead map.

As I continued to build out the solution I found it more helpful to build up item templates for each view and use data binding to wire up the ARItem to the visual. The BingAR sample is a good example of this. I created a class called RestaurantItem that inherits from ARItem and adds properties like Cuisine and UserRating. Then I changed the default item template for WorldViewItem to be a rounded rectangle with fields in it that bind to the custom properties on RestaurantItem. The same could be done for OverheadMap.

So really, you can show as complex an item as you want. Just use data binding to relate the visuals back to the ARItem object.

I understand what you are saying, but i think that relates more to the way to see a point item, not other type of geometry. What i mean is that instead of having points (X,Y, altitude), I want to add lines and polygons to the ARDisplay. In that case an ARItem should be a set of connected points. I would use that to see a pipeline over the street which is underground, or any other geographic object with line or polygon geometry. Then comes the way I want to draw them on the screen, for what I will have to define a template and all that. Do you think it would be possible to extend the GART to include this? or the GART paradigm must be changed in order to support it?