My Google Map Blog

On March 30th, 2017, a fire started under an overpass along the I-85, one of the major routes through Atlanta, Georgia, USA. The fire resulted in a section of the overpass collapsing and major repairs being needed to other sections of the roadway. Google Earth now features an image dated April 1st, just two days after the event. Already we can see work being done to repair the road. According to Wikipedia, repairs were completed by May 13, just six weeks after the collapse.

Collapsed bridge in Atlanta, Georgia.

Almost before the fire was out, people were checking Street View to see what had been under the bridge that could have caused such a major fire. Apparently there were some plastic conduits that had been stored under the bridge:

Conduits stored under the bridge as seen in Street View in March 2017 (the month of the fire)

Using the Google Maps version of Street View, we can go through the historical imagery, which allows us to see that the material was placed there some time between July 2011, and April 2012.

No materials in July 2011.

Materials stored under the bridge by April 2012.

Although in this case, the local government had records of what had been stored there, this sort of event highlights how useful both overhead imagery and Street View can be for quickly and easily checking the recent history of a location. We get quite a lot of emails asking whether we can obtain more imagery than is in Google Earth or Street View to help settle a dispute or identify when some event occurred. Unfortunately, we cannot help in such cases as we do not have access to any imagery not already available on those platforms and Google does not supply imagery for such purposes via other channels either.

There are, however a few things to keep in mind with regards to what is a relatively new public ‘historical record’ of the world:

• How frequently imagery is updated and the resolution of imagery varies significantly from place to place. In many cases, even when Street View or overhead imagery would be suitable for what you want to find out, it simply isn’t available for the dates you are interested in.
• It is not live and there may be a period of months or years between the time imagery is captured and when it is published. It will typically not help you track down a stolen vehicle or find a lost person.
• Be careful with dates. Do not be too trusting of the dates on aerial imagery, especially when it is sourced from third parties. Older aerial imagery in particular is often incorrectly dated. Satellite imagery dates are typically much more reliable. Street View is only dated to the month and we do not know how accurate the dates are.
• A significant proportion of the world doesn’t yet have Street View, and only some areas have high resolution aerial imagery (mostly the continental US, parts of Europe, Japan and New Zealand). Satellite imagery is often only useful for large scale phenomena.

It would be great if Google were to increase the accuracy of the dates on the imagery. The satellite imagery suppliers do know the exact time that each image was captured and it would be fairly easy for Google to have timestamps on the photos used for Street View. So why don’t they? It is possible they are concerned about the privacy implications of time stamps on Street View. They may also be concerned about the possibility of making mistakes. If Google gives an exact timestamp then the expectation that it is accurate is much higher.

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