In the spirit of consistency, I decided to add a shadow to the tooltips (View the example). They just didn't blend in with the rest of the Google Maps overlays. So I set out to replicate the "standard" Google Maps shadows.
Replicating the Shadow
Through a mix of reasoning, instinctive guessing, and trial and error, I have devised a technique to replicate the shadows using Adobe Photoshop. It's a fairly simple process and the steps are outlined below.- Make a copy of the overlay's layers and merge and rasterize the copies if needed
- Make the copy all black (I use a gradient map and set both ends to black)
- Perform a Free Transform and set the Height/Vertical Scale to 50% and the Horizontal Skew to -45°

- Apply the Gaussian Blur filter (I set it to .5 pixels for small images and 2 to 3 pixels for large ones)
- Set the Opacity to 45%
- Save the shadow layer only as a PNG