Google Maps: Insanely Detailed about Ground Zero?

I was trolling around Google Maps this afternoon and noticed something odd about its building details for the WTC construction site, a/k/a Ground Zero. The building outlines they have for NYC are quite accurate, I don't know if they get them from the Department of Buildings or a clutch of gnomes riding around in Prii measuring the dimensions. But I think they've either gone overboard or just have a glitch in their tiles for the former 10248 zip code:

It appears that Google are now displaying the construction trailers dotting the WTC site (though if they're that accurate I'd expect a better job showing the temporary PATH station).

Update: I have no idea what the gray blobs are in the images (perhaps inserted by the demo copy of Pixelmator I used?)

Here's an embedded Google Map which may or may not show what I am writing about depending on various things in the URL which I don't understand:

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