v2.6 QUERYMAPFEATURES may produce inconsistent results

[jng]

The v2.6 QUERYMAPFEATURES works like this:

1. Call MgRenderingService::QueryFeatures() with the given parameters (returns a MgFeatureInformation)
2. Call MgRenderingService::RenderDynamicOverlay() with the given parameters (if inline selection is requested)
3. Call MgRenderingService::QueryFeatureProperties() with the given parameters (if attributes is selected)

All 3 components are then married up to form the final response.

A click-based selection will issue QUERYMAPFEATURES with MAXFEATURES=1. For a map with more than 1 selectable layer (eg. Parcels, Trees), there may be cases where the following happens.

1. Call MgRenderingService::QueryFeatures() with the given parameters. Returns a MgSelection with Parcels selected.
2. Call MgRenderingService::RenderDynamicOverlay() with the given parameters. Returns an image of the selected parcel
3. Call MgRenderingService::QueryFeatureProperties() with the given parameters. Returns the attributes of the first selected Tree. Because MAXFEATURES=1, no attributes for Parcels are returned.

The problem is when a click could select more than one layer, the attributes may be collected for the wrong layer, even if that layer has candidate matching features. When MAXFEATURES=1 and we requested LAYERNAMES=Trees,Parcels and a selection image/XML of Parcels is returned, at this point we only want to collect attributes from Parcels instead of Trees and Parcels.

Basically when we have a MgFeatureInformation, we want to use the layer names within its MgSelection for collecting the matching attributes instead of using the layer names from the original request.