Google Earth Blog

The amazing things about Google Earth


historical imagery

Some sights we missed

On Monday we had a look at recent imagery in Google Earth. We used the Google Earth plugin to find new imagery. However, either our algorithm is not perfect, or Google has added some more imagery since then because we have found a satellite image that we had missed that shows a major flooding event in Japan.

For more about the event and some photos see this article. Note that a few of the photos are of regions of the river upstream of the area covered in the Google Earth image.

We also came across a mudslide in Myanmar. We could not find a news story about it in particular but there were apparently a lot of mudslides in the region.

And finally there are some images of wild fires in Siberia. They are black and white, but still quite spectacular.

See this article for a NASA image showing the extent of the fires and smoke.

To find the locations above in Google Earth download this KML file.

Recent imagery updates review

Google has added quite a lot of imagery to Google Earth recently, especially in Australia and East Asia. We have been using the Google Earth plugin to find new imagery. However, we have been having problems because of a bug we have mentioned in the past, which has Google Earth not showing all historical imagery at all zoom levels. It turns out that this affects the timeline as well and if you are zoomed out too far you do not see many of the dates on the timeline. We found that, as of this writing, almost all imagery dated July or August, 2015, does not show when you are zoomed out. For example, if you look at the whole of Europe, switch to ‘historical imagery’ and step backwards through the timeline, it will go almost daily through October and September and then skip straight to June even though there is imagery in Europe from July and August.

Nevertheless, we did manage to map out a lot of new imagery. We have probably missed some, as our system is not perfect due to the problems mentioned above. There is some overlap with the ‘Satellite imagery updates’ layer found in Edition 2 of the Voyager layer. Also, we have only mapped imagery with recent date stamps (July to date) and as you can see from our colour coded version of the ‘Satellite imagery updates’ layer, Google typically releases a lot of old imagery as well as recent imagery. We have no way of finding the older imagery.

California has seen a lot of large fires this year due to the ongoing drought. We already looked at some of the resulting scars using Landsat imagery. Now Google has added some imagery covering another area where a fire known as the Butte Fire took place.


Burnt area from the Butte Fire is clearly visible.

In our coverage of Google Crisis Response we mentioned a map featuring satellite imagery of flooding in South Carolina. Google has since added some of that imagery to Google Earth.


Flooding in Columbia, South Carolina.

On October 2nd there was a landslide in Santa Catarina Pinula, Guatemala. We learnt about it via DigitalGlobe’s ‘First Look’ map.

This year Black Rock City, the site of the Burning Man festival, has only received one image, captured near the start of the festival. In previous years the festival received much better coverage, including the current 3D imagery, which was captured in 2013.

Also visible in the imagery, are:

  • Sarnia Artwalk, an art festival in Sarnia, Ontario, Canada.
  • Fires in Indonesia similar to ones we already looked at with Landsat imagery.
  • Albuquerque Balloon Fiesta, a Balloon festival in Albuquerque, New Mexico. The image was captured the day after the event ended, so there don’t appear to be any balloons in the image.
  • A new image of the Tianjin crater, showing the area has been cleaned up quite a lot since the explosion.

To see the maps of recent imagery and the locations above download this KML file.

What’s that image, Voyager Edition 2

With the recent release of the ‘Voyager Edition 2’ layers, including a map of recently added imagery, we can, as we have done for previous updates, have a look through the imagery to see if there is anything interesting. We forgot to mention in our previous post on the layer that the dates are all given as one day earlier than the dates displayed in Google Earth. We do not know which dates are correct.

A good place to start when checking to see whether imagery was captured for specific events is DigitalGlobe’s FirstLook map. Many of the locations on the map do feature relevant imagery in the latest Google Earth updates, but not all of the locations have anything interesting to see, or we were unable to find it. It must also be noted that the imagery is useful to first responders in disasters even when not much relating to the disaster is visible in the imagery. In fact, some of the imagery added is years old, but has been obtained to assist first responders as good maps or satellite imagery might not previously have been available.

Note that some of the locations featured are from imagery more recent than the Voyager Edition 2 map.


Flooding in Bulani, Pakistan.


Flooding in Rojhan, Pakistan.


The Hajj pilgrimage, Mecca, captured a few days before the official start of the Hajj.


Hellfest Open Air 2015 in Clisson, France.


Oktoberfest in Munich, Germany.

To find the above locations and more in Google Earth, download this KML file.

Seeing imperfect orthorectifcation in Google Earth imagery

Yesterday we talked about orthorectification and how it is imperfect, especially when using an inaccurate terrain model. We thought we would have a look at the effect using historical imagery. We used a variation on two JavaScript tools we have created in the past for animating historical imagery using the Google Earth plugin and using Google Earth Tours. This enabled us to create tours which animate only a selection of historical imagery and exclude lower quality images. Because Google Earth does not allow us to play the tours at a reasonable speed (it omits images), we recorded the tours and then sped up the recording.

We chose three locations that we know have significant elevation variation as well as a lot of satellite imagery. They are Devil’s Peak, Cape Town, South Africa, Rio de Janeiro, Brazil, and Calama, Chile.

If you look carefully, you can see that some locations move more than others.

The buildings at 1 and the bridge at 2 seem to move much less than the surrounding imagery. This suggests that the terrain model for these locations is closer to the true altitude than for surrounding areas.

You can download the Google Earth tours we used to create the video here.

Google Maps API Maximum Zoom – Part 6: Resolution

We have recently been looking at our map created from the Google Maps API’s Maximum Zoom data:
Google Maps API Maximum Zoom – Part 1: Data collection
Google Maps API Maximum Zoom – Part 2: Overview
Google Maps API Maximum Zoom – Part 3: Starting on a more detailed look
Google Maps API Maximum Zoom – Part 4: Continuing the detailed look
Google Maps API Maximum Zoom – Part 5: A detailed look – the Americas

As we have mentioned before, the maximum zoom available in Google Maps varies between 7 and 22. However, if we correct for the magnification at the poles, the minimum becomes 9. Below you can see samples of imagery at some of the zoom levels. We have skipped over a few levels either due to lack of imagery, or because they are too close to see much difference. Note the scale on each image.

We have corrected for the magnification at the poles and then separated out each zoom level into its own overlay, so if say you want to find all Landsat imagery (Zoom level 16) then you can display just that.

To view the overlays in Google Earth, download this KML file

When looking at the highest zoom level our map only picked up very high resolution imagery in Europe. However, this is partly because our survey was not fine enough to pick up small patches of high resolution, such as: