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How can I make the symbology of a layer dependent on the visibility of another layer?

October 31 2007 | 0 comments
Categories: Cartographic Effects, Symbology

How can I make the symbology of a layer dependent on the visibility of another layer? For example, the color of parcel lines would change if the aerial photo layer is turned on.

Mapping Center Answer:

I’m afraid there is no way to do that. It actually involves a double switch, so not only turning on the imagery friendly parcel symbology, but also turning off the regular parcel symbology. It’s an interesting idea, I’ll let the development team know about it.

In the meantime, one trick I’ve used is to create a multi-layer line symbol where one layer is offset (below) the regular symbol and uses the same color as the background for the regular map (e.g. white). Then when you turn the imagery on, the slightly offset highlight will show in the dark areas of the image where the normal parcel line would not, and in the very bright areas of the image, the regular parcel lines will continue to work. As long as people are zoomed in when using that symbology (showing fewer than 200 parcels) it should perform decently. You could use scale ranges to set that up.

Another trick with parcels is that you can make them something like 20% transparent at smaller scales when viewed with imagery, allow people to see where the parcels are, then when they zoom in you change the symbology to something that allows them to get their work done. All that would be done by having scale ranges set on group layers, one for small scales, one for medium scales, and one for large scales (at least that’s the easy way to build and test the map; once it works, switch the groups to be called parcels and imagery, where each group layer has a layer for small, medium, and large scale displays, and instead of setting the scale range at the group layer [which should be turned off in this arrangement] set the scale range for each constituent layer).

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