As for the glow stuff, I have yet to use it. The stroke thing is something I can help with. I assume that you have a mask for the land, and that you are actually using Gimp. I am almost sure that it works the same in PS, but I don't use it so...... Anyhoot, go to the channel tab and right click on the mask mentioned above, then choose "Channel to Selection". Now either go to your land layer, or even create a new layer to place your stroke on, which might be better anyway. Once in the desired layer (highlighted in the Layer Window) go to the Edit menu and near the bottom you will find "Stroke Selection", click that and the Stroke window will pop up and here you can select the width of the stroke, line type and other stuff as well.

And there you go. Experiment and have fun.