Gooogle Earth / After Effects question: how to seamlessly animate an encircled army on a map???

[ninose11]

Hello everyone, I've been seeing a lot of these animated war maps using Google Earth and After Effects, but I can't figure out how they're animating the encircled armies so seamlessly. I'm assuming it's two layers, a red layer (invaded layer) and a blue layer on top encircling the red layer. What I can't figure out is how seamless the encirclement looks. The animated encircling blue layer has a white stroke to it, but as the blue layer encircles the red layer, the white stroke doesn't overlap itself. Does anyone know how to do that in After Effects? I've already asked on youtube but haven't received any answers yet. So I figured I'd try the After Effects forum. Thank you in advance.

https://youtu.be/xS1V5NvZrac?t=34 

[Airweb_AE]

Simply add a stroke and a mask, then animate them.

I animated the mask using the Mask Expansion property, but you also have the option to animate the path point by point.

[ninose11]

Thank you so much for your help Airweb_AE.  What I'm hoping to do is a little like what you see in that youtube animation. I believe the animate shape on that youtube video I posted is a shape rather than a mask, though I may be wrong. But my reason for thinking that is that the blob moving across the map has a stroke applied to it.  

[Airweb_AE]

In my first video if you look carefully, there is a stroke.

[ninose11]

Yes, I saw that. But in these youtube videos it seems like those invading shape layers are changing their shape much more fluidly than I've seen in After Effects. I looked into it a little, and I discovered that these invasion videos are done with a program called "FlipaClip". And it looks like these animated invasions are done frame by frame, painting a layer over an over to make it change it's shape. Do you know if there's any After Effects plugin that can do this? - fluidly change a layer's shape?