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  • Usual Methods Don't Work with Overlapping Data in One Map Layer

    These usual methods for identifying and reporting on displayed map features don't work when a map layer has overlapping map features:

    • Map tips

      Most MapGuide layers show a yellow "map tip" when the mouse cursor is moved over a map feature. Map tips usually show identifying information for map features, such as parcel code, address and owner name for parcels. Map tips only show information for whatever layer is "on top" at the location of the mouse cursor. For instance, to see Subdivision layer map tips, we've learned to turn off the transparent Parcel layer that is higher in the legend and, thus, "on top" of the Subdivision layer which is lower in the legend.

      Map tips are an unreliable source of information when one layer has overlapping map features because the feature we want may be "underneath" another map feature in that same layer. Individual map features cannot be turned off to reveal hidden features underneath when the map features are in the same layer.

    • Looking at displayed map features

      For a layer that doesn't have overlapping data, we can see all of the map layer's features displayed.

      For overlapping map features, what you see on the map is an unreliable source of information. The feature we want may be "underneath" another map feature in that same layer. By just looking we have no way of knowing how many map features might be "stacked" on top of each other or even if there is one or more features underneath! When a layer with overlaps map features are translucent or transparent, we may be able to see edges of map features under the top feature, but map features of the exact size and shape may be stacked on top of each other, preventing us from "seeing" anything except the one "on top".

    • Double-clicking to get more information on one map feature

      Like map tips, double-clicking to get more information on one map feature only works for whatever layer is "on top" at the location of the double-click. Continuing with our Parcels/Subdivision example, when the Subdivision layer is on along with the default Parcels layer, double-clicking shows data for the parcel, not the subdivision. It's necessary to turn off the default Parcels layer to double-click on a subdivision area.

      Double-clicking is an unreliable source of information when one layer has overlapping map features because the feature we want may be "underneath" another map feature in that same layer and we have no way of removing the map feature that is on top.

    • Traditional MapGuide Reports

      Selecting map features and choosing a report of those selected map features is exactly what we need to get information on displayed overlapping map features in one map layer! However, traditional MapGuide reports selected with the "View Report" tool on the MapGuide tool bar or by right-clicking in the map and choosing "Reports" from the right-click menu do not work for layers that have overlapping map features.

      Layers with overlapping map features have special reports accessible through the "Map Tools & Map Info." drop-down list in the title frame at the top of the map.

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