I’m liking Leaflet. It’s got all the great flexibility I love in Polymaps, quickly compositing various layers of raster and vector data into one fancy map. But unlike Polymaps it runs well on iOS devices. And it’s got an active community; Polymaps feels like a dead end.
A few things are missing:
There’s no way to specify the z-ordering of layers, it’s all just in whatever order they are. The developers have said they’re working on this. (Z ordering basically doesn’t exist in SVG, it’s all document order. That’s dumb.)
Scaling transitions aren’t beautiful. Leaflet animates the raster layer but hides my vectors and then has them blink back into place. Bah.
Screenshot of work in progress. Lots going on here… Purple is steps. Orange squiggles are my walks. Faded = older walks. Redder = longer walks. There’s some interaction, too. Click on a track to highlight it and get a popup showing length and age.