Adding data to a feature

Discussion created by ddelapasse on Oct 24, 2013
I am able to add content using the REST api's AddItem to create a list of lat/longs.  However, in my workflow I would like to create one feature and then add data to it periodically (via REST api).  Looking at the API I see UpdateItem, but I can't tell from the tiny description if it will  replace the item's data or add to it.  Would that work to ADD points?  If not, what is the correct way to do that?