A lot of people wonder about Google Earth imagery. Why is the image of my house so old? Why can’t I get a picture of my car accident from a month ago? Why doesn’t Google get newer pictures? This article gives a broad perspective about how Google gets the imagery and why it’s hard to get more recent imagery. It also provides you with ways to see lots more imagery built in to Google Earth by showing you where to look.
You would be surprised how many people initially think Google Earth (GE) will show imagery in real-time. Or, that surely it will only be a day or two old. I guess part of this thinking comes from watching the news deliver weather satellite photos which are only a few hours old, or spy TV shows with “live” satellite imagery (that’s pretty much science fiction except in rare expensive military operations). But, the problems of getting quality high resolution imagery are very challenging. Weather satellites are at geosynchronous orbits (36,000 km) and take low resolution imagery. High resolution satellites (e.g. those operated by commercial satellite companies like DigitalGlobe or by the government/military) operate just a few hundred kilometers above the Earth. This means they only see a small part of the Earth with their camera as they orbit over. They typically go around the Earth every 90 minutes, but only cover about 1% of the Earth on each pass – but, most of the area covered in a pass is water. Not only that, but imagery for Google Earth is only going to be good if the sun is at a high angle when the satellite goes over (fewer shadows), when there are no clouds, and as little haze/pollution as possible. Believe it or not, the times when all these factors come together are pretty rare. It can take months or years for a good quality image to be taken by satellite even if you pay lots of money!
Once the imagery is taken, it takes time to process the data before it is available to customers. Google is one of these customers (a really big one). Google has to evaluate the new imagery against the current imagery to determine whether the new is better than the current. They have computers to automate as much of this as possible. But, for important areas with large populations the process to check and verify the quality takes time. Once an image is selected, it has to be processed into the format and coordinate system of Google Earth’s databases. Then it has to go through a quality control process and fed into a processing system before it gets distributed to the live Google Earth database servers. This is one reason why you usually do not find any imagery younger than about 6 months in Google Earth and Maps. And why updates usually only happen about once every 30 days.
Not all the imagery in Google Earth comes from satellites. A lot of the imagery comes from aerial photographers – mostly in airplanes with special high resolution cameras. Some of the imagery even comes from kites, balloons, and drones. Google acquires imagery from a variety of sources. Some of the imagery is given to Google by city or state governments. The age of the imagery varies greatly, but most of the high resolution imagery is between 6 months and 5 years of age. Again, because the imagery comes from a variety of sources, the process to get this imagery into Google Earth is complex and involves a great deal of time and effort.
Another reason why you don’t find imagery that is newer is that it can cost a great deal of money to acquire quality aerial imagery. The companies who spend this money need a way to recover their costs. More recent imagery is more valuable than older imagery. As a result, these companies are reluctant to have their newest imagery available for free for anyone to view in Google Earth. Read the agreements for Google Earth before you try to use its imagery for business applications (more information). You can’t sell or use the imagery from Google Earth for business purposes without permission.
Google has been known to release much more recent imagery in GE for unique events. For example, for the 2008 Beijing Olympics Google released 2-week old imagery for the Beijing area.
However, near real-time imagery of Earth is available in Google Earth! “What?! After all that you are saying it is available?” you ask. Sure, there’s the Weather->Clouds layer. The clouds are actually taken from weather satellites and are a global picture of the clouds as recent as 3 hours old. Ok, so that’s not the kind of imagery you were thinking about?
There used to be a cool layer for Google Earth from NASA which showed the entire Earth at a medium resolution (about 250 meter resolution per pixel). The imagery was taken by the MODIS Terra satellite and was processed as quickly as possible and showed the entire Earth between 6 – 12 hours old. The imagery was continuously updating. You could see dust storms, large fires, volcanoes, haze conditions, droughts, floods, and – of course – clouds. This was the most recent, highest resolution imagery of the Earth continuously updating available to the general public, but it’s not available now. But, the resolution was too low to see things like your house or car clearly. There are a few new commercial companies launching multiple low-earth-orbit satellites in an attempt to get more near-real-time imagery of the Earth at at least medium-resolution, at an even more frequent update rate. We’ll be following these efforts closely, and hope layers to view them will appear in Google Earth.
Since Google Earth version 5, Google has the historical imagery feature, so you’re not limited to just the imagery shown by default in Google Earth. Google has archives of imagery from many sources and dates. For many places, Google has 2, 3, or even 30 different images over time for any one location (sometimes decades old). In some cases, you can even find newer imagery than the one shown by default. Usually in a case where the older imagery looks better overall than the newer. The historical imagery feature is a an amazing resource, which I encourage everyone to check out.
Let’s not forget to mention Google’s ground-level Street View imagery which is increasingly available in places all over the planet (viewable in Google Earth and Maps as well as on mobile). But, can also be months or years old for similar reasons (challenges of covering the entire planet and processing huge amounts of data).
Anyway, I hope this article helps provide a better understanding of the imagery in Google Earth and how it all works. This is a high-level overview and is based on my own observations and opinions. Feel free to comment below. (Originally posted Feb 2008)
[NOTE: The 2009 version of this article is also available in Spanish.]
About Frank Taylor
Frank Taylor started the Google Earth Blog in July, 2005 shortly after Google Earth was first released. He has worked with 3D computer graphics and VR for many years and was very impressed with this exciting product. Frank completed a 5.5 year circumnavigation of the earth by sailboat in June 2015 which you can read about at Tahina Expedition, and is a licensed pilot, backpacker, diver, and photographer.
Nice one Frank 😀
Now 2016, still showing the maps prior to 2012. Not all its hyped up to be.
Dwight Nadeau says
Why does it take a long time for the newest default imagery to get into the historical imagery layer?
But still no “imagery_update.kml”. Last one dates back 2 months and a half (January 21st).
Seems they dropped this really nice feature. Usually the KML file framing the imagery updates is released twice a month.
At least they seem to keep this feature in the “Google Gallery”, so let’s hope the concept of showing the public how imagery is updated is not sacrified (as so many other useful features like the terrain view in google maps).
No new imagery since 21 January?
(Only one possible batch reported in GEB)
Leonardo Leidi says
I am anxious for the KML file. More than a month has passed!
steve jones says
yes – saw myself being born – in 1936!!!
Brent Busch says
When are they going to roll out an update to GE? It’s been 5 months since the last version was released.
When will the new imagery update KML be released? It’s been about two months! BTW Frank, this post is really helpful! 🙂
I too have been wondering about the lack of KML updates since Jan 21st..
Frank can we get an official word about this from Google?
The latest imagery KML seems to have been refreshed; it’s dated February 27th 2014.
Well, well, well … as the KML only just appeared today, they must be reading the Google Earth blog at Google HQ 🙂
And, like the 21 January update, it is MASSIVE. Perhaps more is going to be rolled into each KML, but it would be nice to know from Google.
where are you guys finding the new kml update? when I google it, it still says 1-21
and each KML will be sent to you automatically when Google release it, although recent experience suggests that this may be some time after GEB readers have spotted new imagery.
There is new 3D imagery for Hartford CT. It would be nice if the entire state was in 3D
I agree with you. CT is such a small state. Fairfield and New Haven should have been released in 3d too
New imagery in Indian Ocean where Malaysian Airline plane is supossed to be crashed.
Appears to be new imagery from 2013 for much of northern Essex, UK but only in the historical data.
The 27 February KML indicates that there is new imagery for this part of Essex – but the current default 2006 imagery is of significantly better quality, and the historic layer is the best place for the new stuff IMO.
As ever, the update process is confusing, and the quality of new imagery is very variable.
On 15 April I see new imagery, but without a file KML. Most likely it’s release in March.
Go to USGS earthquake site, at least the imagery is much more current and you can sign up to get email earthquake notifications for your area or anywhere in the world at whatever magnitude level you want down to as low as 2.0 richter scale, as far as I can tell it zooms in to same level as google earth does, you don’t have to register to access site, just give your email if you want the notifications.
Dan Jacobson says
OK, what is the USGS link to a map of e.g., 24N 121E?
Dan Jacobson says
Absolutely nobody to contact at Google to find out why they stopped updating the default (aerial not satellite) Taipei etc. Taiwan urban imagery in 2006.
Timothy Whitehead says
The current aerial imagery is listed as copyright Geoforce Technologies. Possibly this company: http://www.geoforce.com.tw/
Maybe you could contact them and find out if they were the supplier and whether they plan to do an update.
Dan Jacobson says
Yes I called GeoForce yesterday and they said (Taipei) imagery is cut into
180 hectare quadrangles, so even if a military base caused say, an
entire quadrangle to be declared secret by the government (under the
laws I quoted in
there would be no reason Google or anybody else couldn’t buy/refresh other
Taipei quadrangles that they sell everyday.
What really is a shame is one discovers if one doesn’t live in the San
Francisco area and often go to conferences and rub elbows with the
Google staff, there really is no real way to get a word in with them
edgewise, the way they have walled themselves off from communication.
(Official channels not working. Tried them.)
I am not saying that they have walled themselves off intentionally, but
rather that is what happens with every such large company.
Of course Stallman would think I was silly for trying to get
words/questions into Google, and maybe I am.
Mollie Brown says
ok, I was hoping this nice article would say what satellites Google Earth does use…however, it rather glides over that, suggesting Digitalglobe offers high resolution images, but very limited geographically. So, where does GE get the satellite images? I do see that kites, balloons, and aerial photographers contribute….but, what satellites, specifically are used? I understand that NASA provides data as well.
Did I simply miss the answer?
Mollie Brown says
Well, I am such a dummy! About one minute after asking this question, I opened up Googe Earth and looked at the bottom of the images, where the various sources of images and facts are shown…
My street view is at least 5 years old. Lol.
Charity Harbeck says
Great overview! Thanks. I teach students and teachers about Google Earth and how to use it as an educational tool. It is nice to have a resource to help explain why real-time is unavailable. I learned something new today.