I posted this over at Urban Cartography, but thought some people here might be interested too, especially since my test use of this new technology will be to make a map showing the locations and some background data on all still-existing Greene & Greene properties here in California.

I was all excited to learn that Google is now allowing user-created
data in custom maps. This is great! However, when I went to go play
with it, I learned the current implementation – which in most ways is
an alpha release – is missing 90% of what could make it useful. Such as:

• the ability to import, not just export, addresses. I want to
  make a canonical map of all currently existing properties by the late
  great architects Greene & Greene; this is not very easy by
  hand-entering every single one. However, if I could import
  tab-delimited text, I could have the full list of 200 up in a few
  minutes!
• the ability to display multiple maps at once – on top of each other
  (i.e., LAYERS). this would make google maps a useful tool for data
  analysis: you could display maps of different data layers at once, but
  what would make this feature REALLY shine would be…
• the ability to pipe in data from online databases. if you combined
  #1 with the ability to bring data in from online databases, not just
  uploaded text files, you could use this with the ability to see
  different layers at once to see real causality – that is, you could see
  how income, for example, and property values, tax base, parks, etc. all
  interact. It would be a really democratic tool – the ability, for
  example, to see if public works projects actually happen in poor
  neighborhoods as they do in rich, or to see what zipcodes public
  university admissions come from (if that data were available), or to
  see what area codes had the most telemarketer calls originating, etc.
  In fact, this would turn Google Maps into the ultimate social
  researcher’s dream tool – the killer app that sociologists, activists,
  criminologists and others have been waiting for.

Just a few (big) suggestions for the Google Maps folks to think about…