Blur, glow, dropshadows, it's all coming around the corner in ArcGIS Online but for now here's a simple fast and easy way to get a firefly effect for ArcGIS Online lines and polygons.
Check out some other social channels where I share how-to's and updates on random map adventures:
http://adventuresinmapping.com
https://www.esri.com/arcgis-blog/auth...
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