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voyager layer

Voyager Layer Edition 2: Satellite imagery updates

Yesterday Google released Edition 2 of the ‘Voyager layer’. As we did for Edition 1, today we are having a more detailed look at the ‘Satellite imagery updates’ sublayer.

The layer itself does not give any dates as to when the imagery was added to Google Earth. As of this writing some of the imagery marked has not yet made it into ‘historical imagery’, and if it is not in the default layer, cannot be viewed at all. There is some overlap between it and the imagery we found using the Google Earth plugin. However, it does not include the image of the crater in Tianjin that was also recently added and is also not yet in ‘historical imagery’. All this suggests that it includes a number of recent updates, but not the most recent, and not all the updates since Edition 1 of the Voyager layer.

The most recent images in the collection are a pair of images captured on September 9th, 2015, of Tingri in Tibet, China.

The oldest image is the only image from 2007 and is of Chitrāl, Pakistan, and together with an image from August 11th, 2015 was probably added to assist with flood relief efforts in the region. Next oldest is an image from 2010 of a strip of Myanmar, again probably relating to flooding. We cannot yet investigate further, as these particular images are not yet in historical imagery, nor in the default layer. Both countries do feature other recent imagery in the default layer that is not listed in this layer.

Here are the total areas of the imagery by continent, (calculated using this useful site). Keep in mind that this is more than the actual total area covered, as some of the imagery overlaps.

Continent Area in sq kms
Africa 434,053
Asia 1,024,896
South America 343,138
Australia 38,891
Europe 634,952
North America 398,701
Oceans & Islands 57,180

We have also colour coded the layer by date which you can see in Google Earth by downloading this KML file.

3D cities layer: another look

Last month in celebration of the ten year anniversary of Google Earth, Google added some new layers under the heading ‘Voyager’. We already had a look at the new ‘3D cities’ layer last week. However, as we showed you with the ‘Satellite imagery updates’ layer, it is possible to download the layer data and import it into excel for further analysis. So today, we are doing that for the ‘3D cities’ layer. Specifically, we are interested in the population figures that are displayed in the popups.

First, we need to point out that we do not know how accurate the population figures provided are. We do not know what sources Google uses for population data. Also, we do not know to what extent the population figures correspond to the actual areas covered with 3D. There are four locations with a population of zero: two football stadiums in Brazil, Black Rock City in the US and Arches National Park in the US. There were also twenty small towns in the US with a stated population of 333. This suggests they were merely estimated. Similar patterns occur elsewhere such as three towns in Bulgaria each having a population of 6,699.


Buenos Aires, Argentina, has the largest single population figure, but this isn’t necessarily the largest population covered by a single 3D mesh, as many places have multiple triangles per mesh.

Given the above caveats here are the population figures by continent:

Continent Population % of total
Africa 1,730,976 0.5
Australia 5,980,800 1.6
Asia 33,584,272 9.3
South America 39,630,909 10.9
Europe 133,978,334 36.9
North America 147,810,132 40.8
Total 362,715,423

 

Note that South Africa is the only country represented in Africa and Japan is the only country represented in Asia. Australia and New Zealand are counted in the continent of Australia.

Here are the figures by country:

Country Population
Ireland 33,262
Serbia 37,804
Luxembourg 77,853
Montenegro 140,997
Greece 161,068
New Zealand 776,234
Netherlands 873,576
Portugal 914,069
Sweden 925,027
Croatia 1,070,016
Finland 1,154,431
Denmark 1,722,610
South Africa 1,730,976
Norway 1,862,483
Czech Republic 2,445,534
Switzerland 2,640,162
Poland 2,683,702
Belgium 2,707,986
Bulgaria 2,759,257
Austria 2,849,803
Hungary 3,268,712
Romania 4,740,262
Australia 5,204,566
Chile 5,787,730
Argentina 12,704,129
Spain 15,687,278
Canada 16,196,329
France 17,242,280
Mexico 18,493,719
United Kingdom 20,589,299
Brazil 21,139,050
Germany 21,412,939
Italy 25,977,924
Japan 33,584,272
United States 113,120,084
Total 362,715,423

 
Japan is the second largest, which is not surprising when you realise that Tokyo alone is listed as having a population of over 8 million.

Satellite imagery updates layer: another look

A couple of weeks ago we had a look at Google Earth’s new ‘Satellite imagery updates’ layer. One notable feature of the new layers is that they can be put into your ‘My Places’ and then exported to KML. Previously, Google would release update maps via a Google map. Although it was possible to view it in Google Earth, there was no way to save it as KML. Today, we are having a look at what sort of things can be done when you have direct access to the data.

In our previous post on this layer we used this website to extract the areas of the different images and then used MS Excel to work out the total areas of the new imagery by continent:

Continent Area (sq. km)
Asia 342,988
North America 314,332
Africa 125,841
Europe 100,481
South America 43,019
Australia 20,346
Oceans & Islands 6,098
Total 953,104

 
Another thing we can do is get the dates of the imagery into Excel. To do this, we exported each continent as a KML file, renamed them to *.xml and then opened them in Excel as XML files. We then combined them into one spreadsheet.

Now we can find out which is the oldest and newest image in the collection. The oldest is a strip of imagery captured on November 5th 2010, in Tibet, China. This is one of many old images in the region that were added by Google to help aid workers in the region in the aftermath of the Nepal earthquake. The newest is a pair of images captured on June 5th, 2015, in Hunan Province, China.

We can also get a better overall picture of the age of the imagery by counting the images by year:

Year # of images
2010 4
2011 6
2012 19
2013 16
2014 41
2015 767

 
and breaking 2015 down into months:

Month # of images
January, 2015 1
February, 2015 5
March, 2015 19
April, 2015 259
May, 2015 459
June, 2015 24

 
Another fun thing we can do is reproduce the KML colour coded by date. We had to figure out how to export XML from Excel, and with a little help with the colour scheme from this site we were able to produce this KML file. So download it now and try it out!

We would love it if Google were to include in the metadata the imagery provider and whether it is satellite imagery or aerial imagery.

New Google Earth layers suggestion: What’s that image?

Over the last few posts we have been having a look at Google Earth’s new layers that make up the new ‘Voyager’ layer:
‘Satellite imagery updates’ layer
‘Earth View landscapes’ layer
‘Street View highlights’ layer
‘3D cities’ layer

Today, we would like to suggest a new layer to Google that would fit well in the Voyager layer. The new layer we are thinking of would feature Placemarks around the world highlighting interesting things that can be seen in specific images. We are not thinking of the sort of things that Google Earth users can find for themselves and make collections of, as such collections already exist on the Google Earth Community, which already has its own layer (found in the Gallery layer). Instead, we are thinking of particular events for which satellite or aerial imagery was specially captured, but may not at first be obvious to the casual user.

Google adds imagery to Google Earth for two basic reasons. The first and most common, is to improve coverage and provide a history of coverage with ‘historical imagery’. The second is when there is something of particular interest in the imagery. This type of imagery is often fairly easy to pick out, as it consists of poor quality imagery, such as containing high levels of cloud cover, or being in black and white, and often there will be a number of images of a particular place over a short space of time.

The best examples of this type of imagery are the images showing tornado damage in the USA. For examples see this post and you can find the locations in Google Earth using this KML file.

We have found other examples by using DigitalGlobe’s ‘First Look’ coverage map. However, it can be quite tedious to find each location in Google Earth and then check whether Google has obtained the specific imagery.


A black & white image featuring the Isle of Wight Festival on June 11th, 2015 – discovered via DigitalGlobe’s first look map

We recently came across an image of Paris, captured on June 3rd, 2015. The image is in black & white and has high levels of cloud cover. We strongly suspect it contains something of particular interest, but we don’t know what. Google, however, presumably knows what is to be seen in the imagery they add. Otherwise they wouldn’t be adding poor quality imagery to the database.

So, to give an example of a few of the types of Placemarks we would expect to see in such a layer, see this KML file.

New Google Earth layers: 3D Cities

Last week, in honour of Google Earth’s 10 year anniversary, Google added a new collection of layers known as Voyager. We have already had a look at the ‘Satellite imagery updates’ layer, the ‘Earth View landscapes’ layer, and the ‘Street View highlights’ layer. Today we are looking at the ‘3D cities’ layer.

The new ‘3D cities’ layer shows the locations where Google Earth has the automatically generated 3D mesh that Google has been rolling out since 2012. In the past, it was difficult to find which areas had the new 3D. There was a list maintained on Wikipedia but there was no way to view it as a KML in Google Earth. So last September we at GEB created a KML with the outlines of the areas with 3D. We have since maintained it, thanks to the help of GEB readers, who spot new imagery and let us know in the comments of this post. Most of the hard work of outlining the newly discovered areas is being done by GEB reader Anton Rudolfsson. Also thanks to an idea from Anton, we display the imagery colour coded by when it was first discovered (which roughly corresponds to when it was first added by Google), so you can get an idea of how progress is going and also spot the latest additions easily.

Google Earth users who are not readers of GEB, or have not seen our KML, may be surprised by the new layer, as most users do not realize just how much 3D Google has managed to generate or how widespread around the globe it is. Having said that, coverage in Africa and Asia is still sorely lacking, although South Africa did recently start getting coverage.

It is not immediately obvious, but the new layer features two different icons. There are filled in triangles with a point at the top, which indicate ‘Existing coverage’, and triangles with just an outline with the point at the bottom which indicate ‘Latest updates’. Note that this does not necessarily correspond to the age of the actual imagery.


We do like the heat map effect Google has managed to achieve with the new layer.


The GEB maintained version has more information, for those interested in getting into the details. Download our KML file here.