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Archive for December, 2016



New Street View coverage 2016

by Timothy Whitehead on Dec.26, 2016, 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

Today we are looking at progress made by Street View in 2016. The map below shows not just changes to Street View but also some other changes Google has made to Google maps over the course of the year. Subtle changes in the fonts results in much of the text being highlighted. In some cases labels have been moved or removed or added (usually this just means a change to what zoom level they appear at). There are also changes to the coastline of northern Greenland and more minor changes to coastlines and water bodies worldwide. Google has increased the promotion of user contributed views which resulted in blue dots being shown on the map even when zoomed out. In the past, one could only see them when zoomed in quite a long way. Sadly user contributed views still do not work in Google Earth. The blue dots are shown but you cannot view the imagery.

The map does not track updates to Street View where there was already existing Street View.


Changes to the Street View map over 2016. Blue: previously existing Street View, Red: changes to the map including Street View.
Large version

The main new recipients of Street View were:

Reunion in February

Sri Lanka in March

Kyrgyztan in May

Albania and Montenegro in November

Puerto Rico and US Virgin Islands in December

Bangladesh, Mongolia, the Philippines, Indonesia Thailand, and Bolivia saw significant increases in coverage.


A map in Street View on Réunion. See in Street View

The post New Street View coverage 2016 appeared first on Google Earth Blog.

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Why Santa’s base remains a secret

by Timothy Whitehead on Dec.23, 2016, 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

With Christmas this weekend and Santa being tracked around the world, but the exact location of his base near the North Pole remaining secret, it is a good time to talk about why the poles are not very well mapped.

Some of the factors mentioned below actually apply to latitudes above about 50 degrees and help explain the poor imagery in northern Canada, Europe, and Russia.

The North Pole
Google Earth only shows satellite imagery over land (and a small strip of sea along the coastlines). There is some occasional satellite imagery in the oceans to be found in ‘historical imagery’, but it is much harder to find since the recent addition of yearly global mosaics of Landsat/Sentinel-2 imagery. The North Pole is in the middle of the Arctic Ocean and although it is covered in ice, Google Earth shows a map of the sea floor and not satellite imagery.

Sun-synchronous orbits
Almost all imaging satellites follow what is known as a sun-synchronous orbit. Read more about why and what the orbit looks like here and here. A sun-synchronous orbit does not cover the poles. The exact limit varies slightly by satellite. The limit of Landsat imagery is 82.7 degrees. You can see where the imagery ends if you switch to historical imagery then look at the northern edge of Greenland.


The northern limit of Landsat imagery is clearly visible in the global mosaics found in historical imagery.


Zooming in closer, we see there is a strip of near snow-free imagery that is not part of the yearly mosaics, but is probably composed of Landsat imagery gathered across many years.


Also interesting is that Google Earth’s country border outlines are significantly out of alignment in parts of northern Greenland.

At the South Pole an obvious circle marks the southern extent of Landsat imagery. There is a smaller circle near the pole, but we don’t know its origin. Also visible is a ‘seam’ along the antimeridian where the edges of the mosaic don’t quite line up.

Web Mercator
Most web-based maps use the Web Mercator projection. This projection has a number of advantages for web-based maps, but one disadvantage is that it does not cover latitudes above 85.05 degrees. Google Maps doesn’t just have poor mapping around the poles, they are actually off the edge of the map.

We can see an obvious circle in the Arctic Ocean in the global mosaics in historical imagery.

The northern circle is at about 83.6 degrees. This is the limit of the mosaics as created in Google Earth Engine, which is presumably based on the Web Mercator projection. We are not sure why it stops at 83.6 degrees rather than 85.05 or why the mosaics extend further north than the limit of Landsat imagery but don’t appear to in the southern hemisphere.

Light and snow
The poles are in darkness for half the year and even in mid summer, the sun is low on the horizon, which does not make for the best photographic conditions. If you look through Landsat imagery you will find that there is no imagery for the winter months at high latitudes. The Landsat satellites capture imagery even when there is snow cover, but most other satellites tend to avoid snow cover where possible. We had a look at the seasonality of satellite imagery in this post

Scientific and commercial interest
The main scientific and commercial interest near the poles tends to be along the coasts of Antarctica and around the edges of the Arctic ice sheet. Most wildlife is found near the edges of the ice. Scientists mapping ice flow are also mostly interested in the edges, in Antarctica they measure the speed of glaciers and the extent of ice shelves and in the Arctic the measure the yearly changes in the extent of the ice sheet. In the Arctic, commercial interests are in shipping routes and drilling for oil near the coastlines. Overall, there is not a lot of interest in the interior of Antarctica or the region around the North Pole.

Building a station at the North Pole would be difficult because the ice is constantly moving. At the South Pole is the Amundsen–Scott South Pole Station.

The Google Earth graphics engine
The way Google Earth displays imagery is not optimised for the poles, resulting in lines appearing to radiate from the poles. Even if Google were to obtain imagery of the Amundsen–Scott South Pole Station, it is likely it would not be very clear in Google Earth.

The post Why Santa’s base remains a secret appeared first on Google Earth Blog.

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Planet imagery for natural disaster response

by Timothy Whitehead on Dec.22, 2016, 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

Satellite imaging company Planet has a programme for gathering satellite imagery for natural disaster response. Read more about it on the Planet blog. Although direct and timely access to the imagery for first responders requires emailing Planet and getting special access, there is actually quite a lot of imagery publicly available on the ‘disaster data’ page. It includes a list of recent disasters and some associated imagery and in many cases the option to download sets of imagery for the affected areas.


Pamplona, Cagayan Region, Philippines. Before and after Typhoon Haima. Image credit Planet.

Planet’s imagery is medium resolution in the 3-5 metre range, higher resolution than Landsat and Sentinel-2 but lower resolution than DigitalGlobe and CNES / Astrium. For a list of satellites and resolutions see here.

DigitalGlobe has a similar programme called ‘FirstLook’ whose imagery often makes it into Google Earth and much of the imagery we look at on this blog comes from that programme.

The post Planet imagery for natural disaster response appeared first on Google Earth Blog.

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The sinking Millennium Tower, San Francisco

by Timothy Whitehead on Dec.21, 2016, 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

We often feature imagery from the European Copernicus programme’s Sentinel-2 satellite. The programme has other satellites, including Sentinel-1A and Sentinel-1B, that gather radar data rather than imagery. They seem particularly good at measuring altitude changes over time. For example, we saw a map of surface deformation after a major earthquake in Chile.

A recent story on the European Space Agency (esa) website is about how the satellites have been able to determine that the Millennium Tower, a sky scraper in San Francisco, is sinking by a few centimetres per year relative to other buildings in the vicinity.


Image credit: ESA. The colour scale ranges from 40 mm a year away from radar (red) to 40 mm a year towards radar (blue). Green represents stable targets.

Given the sensitivity of this data it makes us wonder whether or not Google could use it to improve the accuracy of their altitude data. We have noted in the past some fairly major errors in their data, such as the sunken island of Gorgona and significant inaccuracies around Rio de Janeiro.

The post The sinking Millennium Tower, San Francisco appeared first on Google Earth Blog.

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