Identify Operation in Map service  and Map Extent

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01-18-2013 05:47 AM
JasonBarney
New Contributor II
I've been working with the identify operation in a Map Service, and I'm confused over the map extent parameter. In my first attempts, I put in some valid extents, and used the same image display provided in some of the online samples. After not getting this to work, I just used firebug and completed an identify in the flex app to get a valid identify url with parameters. Using those parameters I've tested a few scenarios with the service, and there is some behaviour I'm not understanding. If I keep the same geometry for the identify point, and change the extents to a larger area, I do return more results. I would expect this behaviour, based on the tolerance it will select more features. The one I can't explain is if I set my extents to a more appropriate scale so I return 1 record ( which is correct ), I can change the extents to anywhere else on the map, even if the identify point is not within the extents, and it still returns the same correct result. If this is the case, why are extents even required? Does it have anything to do with the selection area ( it doesn't appear so ), or is it simply to mimic the scale level used to do an identify?
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nicogis
MVP Frequent Contributor
The mapExtent and the imageDisplay parameters are used by the server to determine the layers visible in the current extent. They are also used to calculate the distance on the map to search based on the tolerance in screen pixels.
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