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The best of Google Earth for May 2017

mer 31-05-2017

We saw a lot of imagery of flooding this month, including:
* The ongoing flooding in Sri Lanka.
* Flooding in Peru, New Zealand and Madagascar.
* Another look at the Peru floods.
* Flooding in Queensland, Australia.

Using Sentinel-2 imagery we saw two large tornado tracks crossing Canton, Texas.

We had a look at a crack slowly forming in Larsen C ice shelf, Antarctica. When it eventually breaks off, the iceberg created will be about 5000 square kilometres and will be among the largest icebergs ever recorded.

We had a look at a number of landslides in Kyrgyzstan, a country which seems to be particularly prone to landslides.

We did a series of posts looking at satellite and aerial imagery calibration targets around the world. Some were quite difficult to find, but in the end we had quite a large collection.

We enjoyed Google’s April Fool’s joke – a fake data centre on Mars. We also managed to find Mars rover Curiosity’s tracks in Google Maps, and by downloading the full image, were able to find Curiosity herself.

We had a look at some strange patterns and other sights around Jiayuguan, China.

We had a look at how DigitalGlobe managed to transfer its vast archive of imagery (100 petabytes) to the cloud.

DigitalGlobe released imagery of the Mocoa Landslide in Colombia. We also had a look at a remarkably similar event, the Armero Tragedy, that occurred in 1984.

The post The best of Google Earth for May 2017 appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Ongoing Sri Lanka flooding visible in Sentinel-2 imagery

mar 30-05-2017

Sri Lanka is currently experiencing severe flooding across its south-western region, reportedly killing at least 122 people so far. We had a look at Sentinel-2 imagery and were impressed to find some very recent imagery from May 28th, 2017, already available on Amazon Web Services (AWS).

Below you can see the southern city of Matara surrounded by flood waters, as well as the muddy water streaming into the Indian Ocean.

Southern Sri Lanka as seen in Sentinel-2 imagery.

A close up of Matara.

To see the above Sentinel-2 image in Google Earth download this KML file.

The post Ongoing Sri Lanka flooding visible in Sentinel-2 imagery appeared first on Google Earth Blog.

Catégories: Sites Anglophones

The Canton, Texas Tornados with Sentinel-2 imagery

lun 29-05-2017

On April 29th, 2017 a tornado tore through Canton, Texas leaving 5 dead and over 50 injured.

We had a look at the Sentinel-2 imagery of the region and we can see two tornado tracks across Canton:

Two tornado tracks near Canton, Texas.

There were tornadoes reported in nearby Eustace and Caney City. We suspect they are reports of the tornado shown on the left below.

Tornado tracks as far as we could trace them in Sentinel-2 imagery.

Zooming in on Canton, we can see how the track passed over several residential areas.

A section of the left (western) track shows a relatively straight right edge with curved tails coming off the left edge. We believe we can conclude from the shape that the tornado was rotating clockwise. We do not know which direction it was travelling (north or south).

Hopefully, we will see higher resolution DigitalGlobe imagery at a later date.

To see the relevant Sentinel-2 imagery in Google Earth, download this KML file. We have also included the locations of all US tornadoes of 2017 as listed on Wikipedia. Keep in mind that Wikipedia’s tornado locations are often far from accurate.

There have been a number of other strong tornadoes in May, but the relevant Sentinel-2 imagery is not yet available on AWS.

The post The Canton, Texas Tornados with Sentinel-2 imagery appeared first on Google Earth Blog.

Catégories: Sites Anglophones

A massive iceberg slowly forming – Larsen-C

ven 26-05-2017

For the past couple of years, scientists have been watching a crack slowly growing in Antarctica’s fourth largest ice shelf, Larsen-C.

The location of the crack. The arrow shows the direction of propagation.

We downloaded some Sentinel-2 images of the location and can see the approximate extent of the crack as of March 2017:

To view them in Google Earth download this KML file. Warning: older computers may struggle to load the images. We tried viewing the overlays in the new Google Earth, but it could only handle one overlay at a time. Trying to open both at once crashed WebGL.

The European Space Agency ESA (which runs the Sentinel program) produced this video showing how they used Sentinel-1 (a radar imaging satellite) to analyse the movement of the ice:

And for some aerial footage, see this video from the British Antarctic Survey (BAS):

While exploring the area in Landsat imagery we were struck by the beauty of the imagery. These two are our favourites:

Sunset in Antarctica.

Beautiful blue ice.

The post A massive iceberg slowly forming – Larsen-C appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Placemark popups in the new Google Earth

jeu 25-05-2017

Today we are having a look at some things you should know if you are a KML creator with the new browser based Google Earth in mind – with a focus on placemark popups. First, we must note that the new Google Earth is still very much a work in progress, especially with regards to KML support and we can expect major changes to the way it handles KML in the future.

The first thing to note is that the new Google Earth cannot access local files. This is a consequence of being browser based. Browser security does not allow web based applications direct access to files on your local computer. So, if you create a standard KML file which includes links to local images in popups or overlays and open it in the new Google Earth, you will not be able to see the images. If you save the file in the compressed KMZ format, then Google Earth puts the images in the file. That did work for image overlays but not placemark popups. We then tried uploading the KMZ file to Google Drive, as the new Google Earth has built in support for opening files from Google Drive. However, we found that trying to open KMZ files from Google Drive gives an error and only KML files could be opened that way.

Finally, we uploaded the image to GEB and linked it in the KML. When we did this, we found that the images did work correctly in placemarks and image overlays, but photo overlays appear to not be working at this time.

The next thing to note, is that when you place an image in a placemark popup, Google Earth does not know how large the image is until it is loaded. The consequence of this is that in Google Earth classic, the popup may be resized after the image loads. In the new Google Earth, this does not happen. If you close it and open it again, the image has been cached and it opens at the correct size:

Left: Opened for the first time. Right: Opened the second time.

The solution to this it to give the image an explicit size in your popup. An alternative would be to wrap your placemark content in a ‘div’ that has explicit style information.

Always include width and height for your images for better popups. This is true even for Google Earth classic.

Another option is to take advantage of the new popup options. We know of three new modes, ‘card’, ‘panel’ and ‘fullscreen’.

To use them, you have to edit the kml file and put one of these lines in the style information for a popup:


See an example of how it is done by inspecting the contents of this sample KML file

The ‘card’ mode does not seem to render HTML:

Also, when you click on it, it opens it full screen. We have not yet figured out how to specify the image. We believe it is intended only for Google’s use and links to Google Maps data via a custom tag: <gx:mid>

The ‘panel’ mode opens in a side panel and we have seen GE Teach make great use of that mode. However, we found that using it on a plain placemark with a single image, it sometimes did not display the image.

The ‘fullscreen’ option displays the contents of the popup full screen and appears to work reasonably well with a simple image.

The post Placemark popups in the new Google Earth appeared first on Google Earth Blog.

Catégories: Sites Anglophones

The Kurbu-Tash and Ayu landslides in Kyrgyzstan

mer 24-05-2017

In March this year we had a look at landslides in Kyrgyzstan and noted just how frequent landslides there appear to be.

Just a month after that post, two more major landslides occurred to the southeast of the region we looked at before. On April 24th a very large landslide engulfed the village of Kurbu-Tash, burying 11 houses, a school, a kindergarten, a mosque and a medical facility. Luckily, nobody appears to have been harmed in that event. Then on April 29th, a much smaller but more deadly landslide, killed 24 people in the village of Ayu. For more on both landslides, including ground level photos and video, see The Landslide Blog (1 2 3).

You can see before and after images using Landsat imagery on NASA’s Earth Observatory website. However, the latest Landsat image was not available on Amazon Web Services at the time of writing, so we instead got a Sentinel-2 image of the location. Here is a ‘before and after’ of the Kurbu-Tash event.

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Left: CNES / Airbus image from Google Earth. Right: Sentinel-2 image dated May 19th, 2017.

The landslide flowed south to north, burying buildings near the end of its run. The total length of the landslide is around 5 km. Also note the small lake that has formed uphill from the landslide. This is known as a ‘landslide dam’, a topic we covered last year. Such dams can be potentially catastrophic if enough water builds up, overflows and suddenly erodes the dam.

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The Ayu landslide is much harder to spot. In fact, we can see at least five other landslides nearby, some of which were larger.

This report states that prior to the Ayu landslide, the Osh region has had at least 25 landslides so far this year, killing six people.

For the locations above, including image overlays using portions of the Sentinel-2 image and the locations of the many landslides we found, download this KML file

The post The Kurbu-Tash and Ayu landslides in Kyrgyzstan appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Calibration Targets 5: Around the World

mar 23-05-2017

This is part of a series on calibration targets. Today we are having a look at various calibration targets around the world.

We start in India at the Shadnagar campus of the National Remote Sensing Centre where there are some calibration patterns specifically for satellite calibration:

This site in India is the only calibration site we know of that uses colours.

This site near Zuunmod, Mongolia appears to have been repainted several times.

We don’t know why the angle was changed slightly in the last repaint.

At Salon-de-Provence, France, we find a basic four square pattern:

Next we have a more complex set of patterns at Mount ShongShan, China. One reference states that there are also two rows of squares near this site, each extending over 2 km but we failed to find them.

The Sjökulla Aerial Test Range, Finland was probably designed primarily for aerial photography, but can also be used by satellites.

In South Africa, there is a single white square near Pretoria:

Designed to be exactly 100 m on a side. We don’t know why it wasn’t aligned with the cardinal directions.

The pattern at Peng-Hu, Taiwan was repainted at a different angle:

There are presumably more around the world, but we failed to find a collection listing them all. Also, in many cases temporary patterns are used, using tarpaulins or, in the case of thermal imaging, metal sheets. You can even buy specially made patterns.

There seems to be no universal agreement on what measurement is ideal. We measured some of the squares and four-square patterns:

Zuunmod, Mongolia: Concrete square on which the pattern is painted – 120 m. Painted four-square pattern – 70 m.
Four-square pattern, Salon-de-Provence, France: 60 m.
Four-square pattern, Peng-Hu, Taiwan: 60 m.
White square near Dunhuang, China: 115 m.
Four-square pattern near Boutou, China: 96 m.
White square, South Africa: 100 m.
Four-square pattern, Stennis Space Centre, USA: 50 m.
Four-square pattern, CalVal facility, India: 140 m.

Also useful for calibrating satellites are a number of sites around the globe whose altitude, colour and temperature have been carefully measured. They are typically dried up lake beds in deserts as such areas tend to be very flat and have a consistent temperature for a given time of day and day of year, and have minimal cloud cover. You can find a collection on the USGS website that has been collaboratively measured by many countries around the world. We have included it in the KML below.

To find the above locations, download this KML file.

The post Calibration Targets 5: Around the World appeared first on Google Earth Blog.

Catégories: Sites Anglophones

The Peru Floods with Google Earth

lun 22-05-2017

A couple of weeks ago we had a look at three different floods around the world, including Lima, Peru. However, the flooding in Peru was very extensive, so today we are looking at some other locations around Peru.

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Here is a ‘before and after’ showing how the Moche River, which passes through Trujillo, Peru, created a new delta:

Moche River delta creation.

Further north we can see how the Chancay River grew significantly wider:

Chancay River. We are seeing it after the water has subsided from it highest levels.

Zooming out and using Landsat imagery, we can see some large areas that were completely flooded. They are naturally swampy areas, but we could not find this extent of flooding in older imagery, so we believe it to be quite unusual.

Left: Google Earth imagery composed of Landsat/Sentinel-2 mosaic. Right: Landsat image from April 4th, 2017.

To find the above locations in Google Earth, download this KML file. We have included an image overlay of the Landsat image. We have also outlined all the 2017 imagery we could find for Peru. If you come across any other 2017 imagery in the region, please let us know in the comments.

The inland parts of Peru drain into the Amazon basin. There was also significant flooding there, but it is rain forest, so it is unlikely that we will see any high resolution satellite imagery (too much cloud cover). It also seems probable that as the water flows towards the ocean we will see floods along the Amazon in Brazil later in the year.

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Catégories: Sites Anglophones

Secret Mars Base found in Google Maps

ven 19-05-2017

Thank you to GEB reader James for sending us this amazing find. If you go to this location in Google Maps / Mars, you will find an image of a secret Mars Base:

After doing some research, we discovered that it is actually a Google Data Centre being built in anticipation of future Mars settlement.

So is it real? Well given that Google posted about it on March 31st, just before April Fool’s day, we think not.

We have previously looked at how to get HiRISE imagery into Google Mars. So we decided to try and find out which image Google used. We are fairly sure it is a section of HiRISE image ESP_037117_1755 captured on 27 June 2014. Unfortunately, Google has only included the colour portion of the image in Google Maps and Curiosity is just off the edge. However, if you know where to look, you can see Curiosity’s tracks going across the image.

Curiosity’s tracks, as seen in Google Maps / Mars

Curiosity as seen in the original image (not included in Google Maps).

If you want to explore the imagery more in Google Mars, download this KML file. We have included a screen shot from Google Maps of the Secret Mars Base, a low resolution version of the original HiRISE image, and a higher resolution version of the relevant area.
We have also marked the location of Curiosity at the time, and if you turn on the Google Mars layer: Mars Gallery->Rovers and Landers->MSL Curiosity Rover (USA)->Traverse Path, then it will help you trace the rover’s tracks in the higher resolution image. We have done our best to line up the imagery with the track. Turn off Mars Gallery->Rovers and Landers->MSL Curiosity Rover (USA)->Gale crater landing site as it adds imagery which will obscure the images in the KML file.

For a number of other posts where we managed to track down almost all the residents of Mars see here.

The post Secret Mars Base found in Google Maps appeared first on Google Earth Blog.

Catégories: Sites Anglophones

The Strange Sights of Jiayuguan

jeu 18-05-2017

We were investigating China’s new Silk Road that has been in the news recently (find various maps via Maps Mania), and we came across some strange shapes in the city of Jiayuguan, China.

The most striking is this square with an ‘X’ and various zig-zag lines.

Next to it are two other shapes.

There are also many other zigzags that look like ditches and what look like power lines of various sizes crossing the area. If any of our readers knows what the shapes are, please let us know in the comments. We don’t think they are ancient ruins, as those are reasonably well documented and consist of a fort and a wall across the pass that is the Western end of the Great Wall of China (which actually consists of lots of separate walls).

Jiayuguan Fort

Nearby there is a large geoglyph apparently made with trees. According to this post it is the Chinese character ‘lóng’ in cursive script.

At 1 kilometre high, it must be a record, but we couldn’t find any references to confirm that.

On the nearby hills, there are three more geoglyphs that are part of the Rhythms of Life series by Andrew Rogers that we covered in 2011. Read more about them here.

“Rhythms of Life”. Part of the Rythms of Life series by Andrew Rogers.

“Caveman”. Part of the Rythms of Life series by Andrew Rogers.

“The Messenger”. Part of the Rythms of Life series by Andrew Rogers.

There are many other interesting patterns in the region such as a wavy line along the railway line that we believe is for drainage, and some buildings and other structures laid out in arrays.

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

The post The Strange Sights of Jiayuguan appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Calibration Targets 4: USA

mer 17-05-2017

This is the fourth in our series on calibration targets. Today we are having a look at a number of locations around the USA.

The first is this interesting pattern at Fort Huachuca, Arizona:

We came across this article which mentions patterns at Walker Field, Maryland and Eglin Air Force Base, Florida amongst others. We couldn’t find a ‘Walker Field, Maryland’ on any map, and try as we might, we couldn’t find the pattern at Eglin Air Force Base, Florida. But we did find a number of interesting sights at Eglin Air Force Base.

We are fairly sure this is a test pattern.

We are not certain whether this is a test pattern or serves some other purpose.

Various markings on this airfield appear to be for calibration.

The spots marked ‘H’ on the runways, are, we believe helicopter landing spots. Do any of our readers know what this symbol means:

Landing spot markings on runway.

There are also no less than 14 separate landing fields in the area. There are also a number of other long structures that we think are probably shooting ranges.

Here is a very old pattern at Cuddeback Lake, California:

A calibration pattern at Cuddeback Lake. There are two more that we have marked in the KML.

There are also two large bulls-eyes at Cuddeback Lake, but we are not sure what their purpose is:

A few more examples from around the USA:

Travis Air Force Base, California.

Beaufort Marine Corps Base, South Carolina.

NASA’s Stennis Space Center, Mississippi.

You may also find this article intersting. It was the source of most of the above locations.

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

Next we will be going international. We have found examples in India and South Africa. If you know of any others around the world, please let us know in the comments.

The post Calibration Targets 4: USA appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Calibration Targets 3: China

mar 16-05-2017

This is the third in our series on calibration targets. Note that such targets are used for both satellite imagery as well as imagery captured from aircraft. Today we are looking at some calibration targets in China and other interesting sites found in the same region.

Thank you to GEB reader Kengrok for pointing us to this site showing a variety of patterns:

Next is a set of lines that we covered back in 2011

Nearby is another similar shape, next to a large square. Plain squares are actually quite common for satellite calibration targets, but this particular square probably serves some other purpose as it is not an exact square and is much larger than is typically used.

Here is a smaller square that at first sight appears to have bomb craters on it, but looking back at when it was either being made or repaired, it looks like the patches were always there.

Older image on the left.

Here are what appear to be fake houses used for target practice. The later deterioration might be due to bombs being dropped on them or it might just be weathering, but the older image certainly looks like they were bombed – but again, we may be mistaken.

Here are some large scale markings that look reminiscent of runways, but we believe were never used as such:

For scale, the small square above and bombed houses are marked with arrows.

We believe these next two are either calibration targets for radar, or tests to see if certain patterns can be used to hide objects from radar:

Although it has nothing to do with satellite calibration as far as we know, there is an enormous scale model of a region from the disputed border between China and India. We previously looked at it in 2006.

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Comparison of the scale model (left) and the region it represents (right).

And finally, here is some giant writing:

We don’t know if it is intended to be read by satellites or from passing aircraft. The ground seems fairly flat so we don’t think it is intended to be read from the ground.

For the locations of all the places mentioned in this post, download this KML file

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Catégories: Sites Anglophones

How do you Move a Vast Imagery Archive?

lun 15-05-2017

Satellite imaging company DigitalGlobe recently wrote an interesting blog post about their vast archive of imagery and how they are moving it to the cloud.

Some interesting statistics from the post:
One image from WorldView-3 can be 30 gigabytes.
The DigitalGlobe archive is around 100 petabytes.
Their archive increases by 10 petabytes per year.

Comparing this to what we learned about Planet’s archive earlier this year, Planet has an archive of 7 petabytes. Before Planet launched the latest batch of 88 satellites and purchased Terra Bella from Google they were adding 7 terabytes daily or 2.5 petabytes per year to their archive. We estimate that they are now adding about two and a half times that daily or over 6 petabytes per year.

So, although Planet has the world’s largest imaging satellite fleet (actually, it is the world’s largest commercially-operated fleet of any type of satellite), their volume of imagery being gathered in terms of data storage required appears to be lower than DigitalGlobe’s. This is probably because DigitalGlobe’s satellites are higher resolution and thus produce much more data per area covered. It is also probable that DigitalGlobe’s satellites gather more optical wavelength bands.

DigitalGlobe have, until now, kept most of their archive in-house in a vast tape-based storage system. However, they are now moving to the cloud (Amazon Web Services). Rather than attempt to upload 100 petabytes to the internet, Amazon sent them a whole shipping container, a solution known as ‘Snowmobile’, complete with built in data storage, which DigitalGlobe then copied their data to and sent it back to Amazon. Interestingly, according to Amazon, 100 petabytes is the upper limit of their ‘Snowmobile’ solution (per truck).

We don’t know the exact size of the Google Earth database, but we estimate it to be several petabytes at least. So if you ever needed an offline version, then you would probably need a large suitcase-sized container at least.

The DigitalGlobe blog post features one of their images showing ‘Snowmobile’ outside DigitalGlobe’s headquarters but that image has not made it into Google Earth. However, we did manage to spot it in Street View:

Ground based imagery looking at an archive of satellite imagery.

The post How do you Move a Vast Imagery Archive? appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Going Back in Time: The Armero Tragedy

ven 12-05-2017

Last week we had a look at the Mocoa Landslide in Colombia. While doing research on that event, we came across a similar, but much bigger event known as the Armero Tragedy, also in Colombia, but it happened in 1985. Google Earth has yearly global mosaics going back to December 1984 (more about the exact date later) created from Landsat and Sentinel-2 imagery. In this particular location there is also imagery from 1970.

The Armero Tragedy was caused by the eruption of the Nevado del Ruiz volcano in Colombia. The eruption melted glaciers on the volcano, causing multiple landslides and mudslides, which later combined together through a narrow valley and then came out on top of the Colombian town of Armero, killing 20,000 of its almost 29,000 inhabitants. Interestingly, the location of Armero is showing in Google Earth as a town named ‘Armero tragedy’.

Looking through the global mosaics in Google Earth’s historical imagery, we can see the enormous mud flow from the tragedy even in the oldest mosaic dated December 1984. So it would appear the mosaic actually incorporates imagery from multiple years or is incorrectly dated, as the tragedy occurred on November 13, 1985. We obtained original Landsat imagery from the USGS’s Earth Explorer, including an image dated November 17th, 1985, just four days after the event, and another one from March 22nd, 1985 for comparison.

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‘Before and After’ of the Armero Tragedy.

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Armero today is just a grid of streets and foundations.

See the relevant parts of the Landsat images in Google Earth with this KML file.

The post Going Back in Time: The Armero Tragedy appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Watching North Korea from above

jeu 11-05-2017

The most recent Google Earth imagery update included some images of Pyongyang dated April 22 and April 23, 2017. It’s a pity they weren’t from a week earlier as North Korea celebrated its 105th anniversary on April 15 with a spectacular march past. There was another march for Army Day on April 25th.

We also came across a story that highlights the dangers of trying to interpret satellite imagery without sufficient background information. There was a story that was published by a number of media outlets that said that North Korea appeared to be building artificial islands with military installations on them. A parallel was drawn with China’s island building efforts in the South China Sea. However, a quick look at the locations mentioned in the story reveals that the islands in question are not artificial. Then the website 38 North published this article, essentially debunking the entire story. It turns out the islands and related construction are just part of a land reclamation project, not unlike many others along North Korea’s coasts. We can see it being constructed starting in 2011 using Google Earth’s Landsat/Sentinel-2 mosaics:

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Speed in milliseconds per image:
Land reclamation wall being constructed.


Not far to the west there is a similar wall that has been there since at least 1984 (the oldest available imagery). Below we show the extent of land reclamation behind the sea wall:

‘Before and after’ showing land reclamation in North Korea 1984 to 2016.

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Another interesting story from 38 North is this one, where they spotted North Koreans apparently playing volley ball near the Punggye-ri nuclear test site. Unfortunately, that imagery has not made it into Google Earth.

For the locations above and some outlines of 2017 imagery, download this KML file.

The post Watching North Korea from above appeared first on Google Earth Blog.

Catégories: Sites Anglophones

Calibration Targets 2: Edwards Air Force Base

mer 10-05-2017

A few weeks ago we had a look at some calibration targets used by the classified Corona spy satellites. Today we are looking at a set of calibration targets and other interesting features at Edwards Air Force Base, California.

We start with one of the most obvious features at the site: The largest compass rose in the world. According to Atlas Obscura its purpose is to help with emergency landings. It was created in the 1930’s long before satellites existed and was designated a National Historic Landmark in 1985.

The compass rose points to Magnetic North.

There are several emergency runways painted on the lake bed, and there are also a couple of very large rulers:

(1) A ruler with markings at each quarter mile. (2) Another ruler with numbered markings at each mile.

(1) Another part of the ruler with quarter mile markers. (2) and (3) Markers used for calibration.

There is also a long row of special calibration markers spread out over 18 miles:

Most of the calibration markers are rectangles containing sets of three white bars in different sizes. This one also features three large squares with three different shades of grey:

Many of the markers have old aircraft or vehicles near by. Presumably used for testing how well the satellite or aircraft camera can identify them.

This marker also has a bullseye

An aircraft, helicopter, pressurised tank and other structures probably also used for testing imaging.

A variety of interesting aircraft on show near one of the entrances to the base.

More aircraft on show at one of the entrances.

Be sure to explore the whole base in Google Earth as there is a lot more to see! We have marked some of the interesting stuff we found in this KML file

The post Calibration Targets 2: Edwards Air Force Base appeared first on Google Earth Blog.

Catégories: Sites Anglophones

A couple of observations about the new Google Earth’s imagery

mar 09-05-2017

When the new Google Earth was released, one of the first things we noticed was the faint Google copyright notices in white, which have long been a feature in Google Maps, but never before seen in Google Earth. At first we thought Google had made the decision to incorporate the copyright notices into the new Earth, but as we discovered last week the new Google Earth uses the same imagery as Google Maps and the copyright notices are baked into the imagery. If we compare the two products, we find that at any given zoom level, the copyright notices are in the exact same locations:

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New Google Earth. Google Maps

Google Earth has long had a problem with image distortion at the poles. The new Google Earth has a similar problem, but generally seems to do much better. Near the North Pole, the sea floor imagery is much clearer in the new Google Earth:

Google Earth Classic. New Google Earth

We can tell that the same original sea floor image was used because there is a white stripe at the antimeridian that can be seen in both versions of Google Earth and Google Maps.

The South Pole has a white circle in the new Google Earth (and Google Maps). This is not a significant problem at this time as Google doesn’t have any good imagery of the South Pole anyway.

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Catégories: Sites Anglophones

Google Earth Imagery Update – Floods around the World

lun 08-05-2017

As we mentioned last week Google recently did an imagery update. The fresh imagery has now been pushed to ‘historical imagery’ and we are looking at three floods around the world.

Lima, Peru
We mentioned Lima, Peru in a previous imagery update. At that time, the imagery was from just before the worst floods. 2017 has seen heavy rains in much of South America with significant flooding in Brazil, Chile, Colombia and Peru. According to Wikipedia, more than 115,000 homes were demolished, leaving approximately 178,000 people homeless. A total of 113 people were killed, 354 were injured, and a further 18 were missing.

The Rímac River flows through Lima and you can see it forming a delta in February and March.

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Speed in milliseconds per image:
Rímac River delta forming in Lima, Peru.


Rímac River, Lima, Peru. In the photo, a foot bridge is partially flooded and a road is damaged. However, we believe that at the height of the floods, most of the surrounding roads were flooded.

New Zealand. Cyclone Debbie.
Cyclone Debbie caused major flooding across the eastern coast of Australia and parts of New Zealand. Last week we had a look at Rockhampton, Queensland, Australia using Sentinel-2 imagery. Below we see some flooding around Edgecumbe, North Island, New Zealand.

Flooding around Edgecumbe, New Zealand.

A closeup of Edgecumbe, New Zealand.

Madagascar – Tropical Cyclone Enawo
Tropical Cyclone Enawo passed over Madagascar in early March causing major flooding along the eastern coast. DigitalGlobe released some spectacular images which, unfortunately, haven’t made their way into Google Earth. However, there is quite a lot of fresh DigitalGlobe imagery, mostly from after the worst of the flooding along the coast. We only found one image captured during the flood:

The region around Maroantsetra, Madagascar

A close up of some houses up-river from Maroantsetra, Madagascar

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


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Catégories: Sites Anglophones

The Mocoa Landslide in DigitalGlobe imagery

ven 05-05-2017

According to Wikipedia, during the pre-dawn hours of 1 April 2017, locally heavy rain triggered flash flooding and landslides in the city of Mocoa, Putumayo, Colombia, killing at least 316 people, injuring 332, and leaving 103 others missing. Technically, the tragedy was not a landslide but rather a mud-flow triggered by many landslides. For some analysis of the cause of the tragedy see the Landslide Blog. It was predicted in 2014.

DigitalGlobe, as part of its Open Data program, has recently released satellite imagery of the location. Although we knew about the event soon after it happened, we had not expected to see any imagery as Mocoa is in a region that has near constant cloud cover, making it difficult to photograph.

DigitalGlobe provides the imagery divided up into squares of 1Gb files with no compression. So even a completely black square that is off the edge of the main image is a 1Gb download! There is a preview of the whole image, but we still ended up downloading almost all the squares to find the right ones as there are no previews of the individual squares.

Mocoa, Colombia, as seen in DigitalGlobe imagery.

Keep in mind that what we are seeing is the debris left behind from the flood. The actual flood waters probably covered some of the houses.

We didn’t download the ‘before’ images from DigitalGlobe so we haven’t done a ‘before and after’. The imagery in Google Earth is so old that such a comparison is not very informative as the town had expanded considerably since the last Google Earth image.

We have cropped and compressed the part of the imagery showing the town of Mocoa and created an image overlay for you to view in Google Earth.

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Catégories: Sites Anglophones

NASA updates ‘Black Marble’

jeu 04-05-2017

NASA has recently released a new version of ‘Black Marble’, also known as ‘Earth City Lights’ or ‘Earth at Night’. The new version is based on 2016 data. The last time they published it was in 2012. The 2012 version can be found in Google Earth’s built in layers under Gallery->NASA->Earth City Lights.

NASA’s ‘Black Marble, 2016’ as seen in Google Earth.

Read more about it on the NASA website, which includes some interesting ‘before and after’s showing the changes that have happened since 2012. They also say that they are working on being able to release daily images of Earth at night some time later this year. This would allow us to see transient events such as power outages.

Also of interest, John Nelson of ArcGIS created this website which takes the 2012 and 2016 maps and shows the differences on a world map that you can explore. Also see his blog post here for a description of how he created it.

Unfortunately, getting the full resolution images into Google Earth would not be easy to achieve. The highest resolution version can be found here and is over 2GB for each image. We were able to make this low resolution version (8MB). For best results, turn off the ‘atmosphere’ (View->atmosphere) and ‘borders and labels’. It also works in the new Google Earth but they haven’t yet added an option to turn off the atmosphere so it doesn’t look as good when zoomed out. To turn off the clouds layer in the new Google Earth, go to Menu->Map Style->Clean.

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Catégories: Sites Anglophones