topic Re: Transparency based on a field attributes in ArcGIS JavaScript Maps SDK Questions

Transparency based on a field attributes

AdrianMarsden — Tue, 07 May 2013 10:07:46 GMT

Not sure I can add more to the title 🙂 Anyone know how I can, either at the ArcMap/Server side on at runtime JSAPI side set transparency of a point layer based on the attribute in a field - the aim is more recent events to have a more solid setting?

Cheers

ACM

Re: Transparency based on a field attributes

SteveCole — Tue, 07 May 2013 14:20:44 GMT

Pretty sure this kind of dynamic transparency isn't supported. You either have transparency for all features in the layer or not. The only hack-ish way I can think of to do this would be something like this:

At load time, get all your point features and determine how many features would go into 10%, 20%, etc groupings.

Sorting your list of features by FeatureID (surrogate for feature "age"), divvy up the features into several different new arrays of features

Now create new featureLayers for each individual array of features and then apply your graduating transparencey to each

FeatureLayer1 (80% transparency)
FeatureLayer2 (60% transparency)
FeatureLayer3 (40% transparency)
FeatureLayer4 (20% transparency)
FeatureLayer5 (0% transparency)

Hopefully you don't need to edit the features. Ugly, ugly, ugly.

Re: Transparency based on a field attributes

AdrianMarsden — Tue, 07 May 2013 14:39:09 GMT

:DI think that is more or less what my colleague is going to do. Thanks anyway.

ACM