gmaps

Earlier this week Google Maps added Mapplets functionality. The feature lets third-party developers offer their GMaps mashups as toggleable layers that can be added to the GMaps interface.

In addition to my duties here at EchoDitto, I also do some work for DCist as a hobby — in fact, I'm pretty sure that my work on this Google Map of the DC subway system helped land me my job. That app has languished, though, functional but limited and still stuck in version 1 of the GMaps API.

So I took a stab at porting it over to the Mapplet format. It went pretty well — you can see the results by clicking here. There were a number of API changes to contend with, though.

First, there was the transition to the GMap2 object, which most of you have probably already done. The Mapplet interface makes initialization much easier — you can count on the map object to already be instantiated — but other parts were confusing. Most notably, Google appears to have finally un-switched the order of the latitude and longitude parameters in their function calls. That's a welcome change, but figuring out how to undo (or double down on) the kludgy solution I was using made things pretty complicated. The subway map was displaying in Antarctica for a little while.

The actual Mapplet is implemented as an XML file based on the Google Gadget spec. You can find an example here, in the Mapplet documentation. It's a pretty straightforward format to work with, although documentation on some of the Google Gadget metadata tags can be a little unclear.