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Tag: sentinel-2

Sentinel-2 imagery starting to shine

by Timothy Whitehead on Jun.01, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

The European Space Agency’s Sentinel-2 programme is almost two years old, with the first satellite, Sentinel-2A, being launched on 3 June 2015 and the second, Sentinel-2B, on March 7th this year. The comparable US run Landsat program has been ongoing since 1972, with the latest satellite in the series being Landsat 8. Sentinel-2 and recent Landsat 8 imagery is available on both Amazon Web Services (AWS) and on Google Cloud.

Sentinel-2 imagery is slightly higher resolution than Landsat 8 imagery, at 10 m per pixel. Landsat 8 imagery is 30 m per pixel for colour, which can be pansharpened to 15 m per pixel.

Sentinel-2 imagery is distributed in smaller tile sizes than Landsat imagery, which we find to be generally more manageable. It does mean that we sometimes have to download multiple tiles for a given area and the colour balancing may end up being different between the tiles. One problem with Sentinel-2 imagery is the provided thumbnails are very small and it is often difficult to tell whether what you are interested in is visible in the image without downloading and processing the whole image. The Landsat imagery is provided with a much larger thumbnail.

Google has taken note of the Sentinel program and now uses Sentinel-2 imagery in conjunction with Landsat imagery when creating their yearly global mosaics.

With the launch of Sentinel-2B in March, Sentinel imagery now covers the earth roughly every 5 days. It is also made available remarkably quickly. When looking at the floods in Sri Lanka we were able to obtain imagery the day after it was captured.

To process Sentinel-2 imagery, we usually use Spectral Discovery for Sentinel-2 Imagery from GeoSage, but it is relatively easy to process it using free tools such as GIMP.

To explore sentinel imagery use our KML for animating Sentinel imagery from this post.


Flooding along the Black River, Arkansas, USA, in May.Copernicus Sentinel data, 2017.

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

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Ongoing Sri Lanka flooding visible in Sentinel-2 imagery

by Timothy Whitehead on May.30, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

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.

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A massive iceberg slowly forming – Larsen-C

by Timothy Whitehead on May.26, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

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.

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The 2017 Queensland Floods in Sentinel-2 imagery

by Timothy Whitehead on May.01, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

In late March, 2017, Tropical Cyclone Debbie crossed the eastern coast of Australia and then moved on to New Zealand. The heavy rainfall resulted in major floods all along its path. The floods were captured in several Sentinel-2 and Landsat images in early April. The best image we could find is a Sentinel-2 image captured on April 8th of the region around Rockhampton, Queensland, Australia.


The city of Rockhampton, Queensland, Australia.Copernicus Sentinel data, 2017.


The region around Rockhampton.Copernicus Sentinel data, 2017.

The imagery was obtained via the archive on Amazon AWS and processed using GeoSage’s Spectral Discovery tool.

As you can see from the measuring stick in this article the recent flood wasn’t the worst on record, but wasn’t far off.

To view the imagery in Google Earth you can download a low resolution version of the whole Sentinel-2 tile and a high resolution version of just the Rockhampton area. We can’t share the full processed image as it is over 350Mb.

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Sentinel 2B successfully launched

by Timothy Whitehead on Mar.08, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

On March 7th, 2017, Arianespace, on behalf of the European Space Agency (ESA) successfully launched the new earth imaging satellite Sentinel-2B. It has identical specifications to Sentinel-2A which has been operating since June 2015. The satellites have identical orbits but are positioned 180° apart, which allows them to cover the earth every 5 days instead of the 10 day intervals that Sentinel-2A was achieving on its own. Read more about it here.

The Sentinel imagery is freely available to the public and can be obtained from several sources, including Amazon’s AWS and the Google Cloud. Using the Amazon AWS source, which provides thumbnail previews, we have created special KMLs that allow you to preview the latest Sentinel imagery and create animations using the thumbnails.

Sentinel imagery is relatively low resolution at 10 m per pixel. It is still useful for very large scale phenomena. It is also used in Google Earth for the historical imagery global mosaics. The mosaics are mostly created from Landsat imagery because the Sentinel imagery only covers mid 2015 onwards. Sentinel imagery is slightly higher resolution, and now higher frequency, than Landsat imagery.

A much longer launch video can be found here.

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Exploring the Chile wildfires with Landsat and Sentinel-2 imagery

by Timothy Whitehead on Feb.23, 2017, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

Yesterday we had a look at some DigitalGlobe imagery of Chile showing the damage caused by wildfires in late January and early February this year.

We thought it would be interesting to explore the region with Landsat and Sentinel-2 imagery.


Landsat imagery. Credit: USGS/NASA Landsat


Sentinel-2 Imagery. Credit: Copernicus Sentinel data, 2017.

The wildfires extended far beyond the area covered by DigitalGlobe imagery (red outlines in the first two images) and almost certainly there were more fires outside the areas shown above, but we did not have time to gather imagery for the whole country. The southernmost Sentinel-2 image was captured earlier than the others and shows at least two wildfires still in progress. Both Landsat and Sentinel-2 imagery clearly show the areas affected by the wildfires and we have outlined them below.

Unfortunately the imagery above is too large for us to share as a KML on this blog.

To obtain the imagery, we started with our KMLs that show previews of Landsat and Sentinel-2 imagery. Once we have selected a suitable image that covers the region of interest in the right date range and without excessive cloud cover, we download the key files from Amazon AWS. For Landsat imagery you need bands 2, 3, 4 and 8 and for Sentinel-2 just bands 2, 3 and 4. We then used GeoSage’s ‘Spectral Discovery’ tools (Landsat Sentinel-2) to process the imagery. An alternative method is to use GIMP or any other suitable image processing tool. GeoSage’s tools certainly make the process much easier, but one downside is the colour processing is automatic, which resulted in significantly different colours for the three Sentinel images.

Obtaining and processing Landsat and Sentinel-2 imagery has certainly become easier over time, with both AWS and Google Cloud hosting the imagery archives. However, what is sorely needed is for a provider to pre-process the imagery and even better would be to then provide it in tiled format. Doing so would change the two public sources of imagery from a niche product mostly used by GIS professionals to a public resource readily available to all.

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