Dead pixel in Google Earth | Hacker News Reader

Dead pixel in Google Earth

helmutsmits.nl

37 pointstobtoh8 comments

Visual artise, Helmut Smits from the Netherlands burnt a 3-foot by 3-foot square into some grass to create a visual prank for Google Earth - a dead pixel on your screen.

No coordinates are provided though - so good luck finding it!

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Funny, but it brings up the question: What is the resolution of the Google Earth satellites? I had no idea. According to the Wikipedia article (http://en.wikipedia.org/wiki/Google_Earth#Resolution_and_acc...):

"This base imagery is 30m multispectral Landsat which is pansharpened with the 15m [panchromatic] Landsat imagery. However, Google is actively replacing this base imagery with 2.5m SPOTImage imagery"

So, it's nowhere near 80cm. But if you read on, you see

"In some areas, local government jurisdictions have submitted more finely gridded terrain models through the Map Content Partners program [44]. In March 2010, the County of Marin, just north of the Golden Gate Bridge by San Francisco, California, published a 40 cm gridded terrain surface of 1425 square km through the program."

40cm, that's nearly unbelievable!

My understanding is that it does vary, depending on source (and their variance is often due to purpose and location).

For example, I'm in a major city so the resolution is great - you can see the boat the previous owners had in the backyard. My parents live in a rural area, and you can't even find their house through the pixels.

Funny thing is that the resolution doesn't always change at what we consider logical places - the town I live in (Waiuku, New Zealand) is split roughly down the middle with high and low resolution - most likely because of the limited availability of high-resolution data. It can be very frustrating when the area you are interested in is just on the other side of the line...

That said, through Land Information New Zealand you can get better aerial detail for free http://www.linz.govt.nz/topography/aerial-images/nzmg-non-ge... at a resolution of 2.5m per pixel.

I'm not sure if google uses this data or not, I guess it's all due to licensing issues etc...

The question "What is the resolution of the Google Earth satellites?" isn't the whole story though. About a year and a half ago there was a quite widely publicised event where Google were flying a light plane filled with cameras over Sydney to take google map pictures.

I don't know if this image of my house is a satellite or plane photo: http://maps.google.com/maps?ll=-33.904944,151.17401&z=21 but those two white rimmed black "squares" on the roof are skylights which are pretty close to 80cm x 80cm. My guess is a single "dead pixel" on imagery at that zoom would be maybe 8 or 10cm across.

[update: make that 3 years ago... http://www.smh.com.au/articles/2007/01/29/1169919256978.html ]

No satellite image can fully capture Newtown; Sydney's very own neighborhood of hipsters and hobos, but also the most cultured and progressive. Nice neighborhood man. Wish I was still there.

The data for Marin county weighed in at 77GB and covered around 520 square miles[1]. The blogger was actually involved in the project and provides a nice link to one of the areas[2][3]. ---

[1] http://blog.simgis.com/2010/03/12/sharing-terrain-with-the-w...

[2] http://blog.simgis.com/2010/04/26/marin-dsm40cm-terrain-in-g...

[3]http://maps.google.com/maps?f=q&source=s_q&hl=en&...

So, what are the geo coordinates of this lawn?

funny idea, I like it

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