The rendering performance can be insufficient when you add a lot points on a map. I would recommend using the dynamic layer for loading shapes according to zoom level and region. Please take a look the Using Dynamic Layer topic of our documentation and the Items Virtualization example.
I have attached two sample solutions which use 100000 random generated points. One of them uses the Dynamic Layer to show points. Second solution uses the information layer. It uses a separate thread to select visible items from item collection. Also it selects visible items when the panning and zooming complete. It prevents hanging of UI thread during user's action.
I hope you can choose the approach which is more preffered for your application.
the Telerik team
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