Is there a way to use Google Maps to estimate empty lots in NYC?

Question

I just came from a presentation by the Manhattan Borough President who said that having a running record of empty lots in New York City is important in regards to available land for potential green space or community gardens is very important. Currently, these numbers are derived from volunteers on the street who also count numbers of homeless. With satellite imagery from Google maps and lots of brains, couldn't this be an automated process? It wouldn't always be accurate due to the lag in available satellite images, but way better and easier than people on the street.

Here's a large empty lot on 46th street and 8th Avenue. http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=8th+avenue+and+47th+street&sll=40.718241,-73.95844&sspn=0.001262,0.00284&ie=UTF8&hq=&hnear=8th+Ave+%26+W+47th+St,+New+York,+10036&ll=40.759899,-73.987089&spn=0.001262,0.00284&t=h&z=19

Many lots (unlike the one above) are simply abandoned spaces that the owners simply don't care about.

I know this is a bit unorthodox for a stackoverflow question but I figured I would throw it out here.

Answer 1

You'd need to decide what constitutes an empty lot and what distinguishes it visibly from above. Match up against parcel data to limit the extent for analysis and you might have something that will give you an index of how 'empty-lot-ish' a parcel appears to be. My feeling is this will only give you a very rough indicator (there is just too much variation) so you will always need someone on the ground to have a look.

This isn't directly related, but you'll also need to look at the Google terms of use, because you usually are not permitted to download the imagery for further analysis. Generally, you can only use it within their API or from Google Earth, or when printed, with clear Google branding or unique Google functionality included. Do analyse the imagery you will almost certainly have to purchase it or come to an agreement with the imagery provider. It might also be worth looking at OpenStreetMap for some open source ideas too.

Perhaps a better use would be to use Google Maps to coordinate volunteers - highlight potential areas of high number of empty lots, highlight correctly zoned areas against plans and provide volunteers a place to record their findings and prevent duplication.