Google Earth Blog

The amazing things about Google Earth


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NASA and Japan make ASTER imagery available for free

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of the instruments on NASA’s Terra satellite. Although it is a NASA satellite, the instrument belongs to Japan’s Ministry of Economy, Trade and Industry (METI). The instrument was launched in 1999 and has captured more than 2.95 million individual scenes since then. On the first of April this year NASA announced that the full catalogue of imagery is being made available to the public at no cost. The instrument, amongst other things, takes stereoscopic images that enables it to calculate altitudes albeit rather low resolution. The elevation data has always been available to the public at no cost.

The most interesting images have been collected in a gallery found here. You can also see some of the more interesting images in this article and this one.


Mt. Etna, when it erupted in July 2001. The full resolution image and description can be found here.


This image shows the 3D capabilities of ASTER. The full resolution image and description can be found here.

To access the full database of imagery, you can use the MADAS (METI AIST Data Archive System). A really nice feature is that it allows you to download the images as network-linked KML files.

The imagery has a similar resolution to Landsat imagery (approximately 30 m per pixel), so is really only suitable for viewing large scale phenomena. As with Landsat imagery its best use would be to see current events before other satellite imagery becomes available. In December last year we used Landsat imagery to look at the scar made by a tornado near Holly Springs, Mississippi. We found it relatively easy to find an ASTER image of the same region captured on March 28th, 2016, and the scar is still visible. Download this KML file to view it in Google Earth.


The image only covers a small part of the tornado’s track.

NASA damage maps

We recently came across this interesting story about damage maps that NASA created after the Nepal earthquakes last year. We dug a little deeper and found this story on the NASA website, which includes a link to the damage maps viewable in Google Earth.

Grab the KML here. Be sure to also check out the layer labelled “NGA_All_Damage_Nepal_April_30th_2015_points“, which is not turned on by default. It shows the location of damage that has been confirmed. It appears to cover a slightly different area than the damage map and we did identify damage in the imagery on the right hand side of the damage map not covered by this layer.

The damage map is clearly not completely accurate, as it does not have a one to one correspondence with the actually identified damage. According to the NASA article it is based on change between satellite radar images between November 24, 2014 and April 29, 2015. As a result, a lot of changes not related to damage have been picked up. At the top left of the damage map a river really stands out. This is because river beds tend to change significantly over time.


The NASA damage map based on changes between radar images.


The map of directly identified damage overlaid on the NASA damage map.

NASA Near Earth Observations in Google Earth

We recently came across an interesting set of animations on YouTube. They are:

The data for the animations comes from NASA Near Earth Observation data. We mentioned this site in 2007, but there is a lot more data available than there was then. We count 71 different datasets, many of which include daily data for most of the world and fairly comprehensive monthly data. We had a look at the Average Cloud Cover map earlier this year.

The YouTube animations above only go up to 2013, but the data is actually available almost to the current date. All the maps can be viewed in Google Earth. Just look to the right of the map under “File Type” and select “Google Earth” and then select the highest resolution available and it will download as a KML file viewable in Google Earth.


Outgoing longwave radiation – September 2015

It is also relatively easy to download a series of images and create an animation similar to the YouTube videos. For example, we created this KMZ file that shows an animation of Solar Insolation for the past year. For best results, click the spanner icon on the timeslider and make sure ‘loop animation’ is ticked. To run the animation click the icon that looks like a combined clock and a play button on the time slider.

Latest Pluto map in Google Earth

Earlier this month, we had a look at a map of Pluto that NASA produced and made available in KML format for viewing Google Earth.

That was before the New Horizons spacecraft had reached Pluto and the image was very blurry. Now the flyby is complete and we are starting to see higher resolution images, including the first high resolution map. It still only includes about half of the surface area and is a monochrome image, but it is considerably higher resolution than the previous version.

The image provided turned out to be too large for Google Earth to display properly, so we had to halve the resolution. Even so, there is a lot of detail in the map and some interesting features to be seen.

To view it for yourself in Google Earth download this KML file. It is best viewed with all layers turned off, and turn off the Earth atmosphere for a more realistic look by de-selecting “View->Atmosphere”.

To see some other planets we have looked at with Google Earth see these posts.
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Google Earth’s ‘background’ imagery

As we have discussed before Google Earth shows different imagery depending on the zoom level and whether or not you are in ‘historical imagery’ mode. We have also talked about how the ocean bathymetry data changes in ‘historical imagery’.

When you are looking at the whole globe in ‘default’ mode, the imagery used for the land was cleverly created by taking Landsat imagery captured over a period of time and automatically removing cloud and snow cover by combining multiple images of each spot. As you zoom in, this transitions to higher resolution satellite or aerial imagery. For much of the world, the individual satellite images or patches of aerial imagery can be identified by means of the ‘historical imagery feature’. However, there are some ‘background’ sets of imagery that are not at first obvious.

If you view the whole globe in ‘historical imagery’ and move the time slider all the way to the left, the image you will see, looks very similar to the Landsat imagery seen in the zoomed out ‘default’ mode. However, this image is a different one and the attribution shows NASA as the provider. It is most likely MODIS data, which comes from Nasa’s Terra and Aqua spacecraft. Now, still in ‘historical imagery’, if you move the timeslider all the way to the right, all the satellite and aerial imagery found in ‘historical imagery’ gets superimposed on top of the background image. However, because the background image is such low resolution it is fairly easy to see where it shows through and there is no other satellite or aerial imagery available to date. If you find one such location, zoom right in, and then switch back to ‘default’ mode instead of the NASA imagery, for most parts of the world, Google Earth shows imagery attributed to CNES/Spot image. This is imagery that has been obtained via an agreement with Spot Image that we first reported on in 2007 when the imagery was first added in parts of Europe. Since then, most of the rest of the world has obtained similar imagery.

None of these ‘background image’ sets have any dates associated with them, nor, as far as we are aware, are they noted on Google’s Imagery update maps when they receive updates.

Left: Landsat imagery as seen in ‘default mode’ when zoomed out. Right: NASA imagery (probably MODIS data) as seen when in ‘historical imagery’ mode.