Script BASIC has been used in embedded controllers for years. (ARM/POSIX) I have the current 2.2 version of Script BASIC running native on Android Linux. (ARM) I think Script BASIC and tablets make a great mobile application development environment. The beauty of Script BASIC is it can morph into about anything you need it to.
It wouldn't be too hard to convert your
GD based web app to a desktop app with the Script BASIC
GFX SDL extension. You could use the alpha channel for more granularity with intensity and pop an info box with the retrieved values if the user clicks on a buoy station. Just saying ...