following a specified point in a feature service

Discussion created by markwwebb on Feb 19, 2014
I am interested in allowing a user to specify an entity (truck, for instance) and only display the other entities (cars, people) that are within an X mile radius of the "truck".  Is this something that is possible?  I know that you can define a geo-fence and alert on entities entering and leaving the fence, but what about a dynamic fence that is anchored on a specified entity? 

I may have a requirement to track multiple "trucks" and all the points around the truck so this solution may need to scale.

Thanks for any help you can provide on this,