My Google Map Blog

Tag: China

The Strange Sights of Jiayuguan

by Timothy Whitehead on May.18, 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

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.

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Calibration Targets 3: China

by Timothy Whitehead on May.16, 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

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.

before
after

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

The post Calibration Targets 3: China appeared first on Google Earth Blog.

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The Jiangsu tornado

by Timothy Whitehead on Sep.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

Although Google has neglected to update ‘historical imagery’ in Google Earth since early June, they have been adding fresh imagery, and when it is reasonably good quality, it goes into the default layer and we can see it. One such instance is a region in Jiangsu Province, China which was struck by a deadly tornado on June 23, 2016. According to Wikipedia, the tornado killed at least 99 people and injured 846 others (152 critically).

We found a number of articles showing various photos of the destruction, such as here, here, here and here. But, actually locating the event proved more difficult. We first mapped out the area that had new imagery and started searching through it for signs of damaged buildings, but with an area of nearly 4,000 square kilometres we were not successful. We did find a raised railway under construction, and a long trail of destroyed houses that turned out to be planned road construction. The articles either mention major nearby cities or small villages that aren’t marked on the map and couldn’t be found through search. Eventually we found mention of “Danping Village of Chenliang Township” and we were able to find Chenliang. From there, the path of destruction was easy to trace over a distance of around 30 km.

To see the path of the tornado in Google Earth download this KML file.


before
after

Although the latest imagery is not very high quality, near total destruction of houses all along the path of the tornado is clear, especially when comparing it with older imagery.

before
after

Some damaged factories.

before
after

A factory roof ripped to shreds.

before
after

See a higher resolution aerial image of this factory in this article

The post The Jiangsu tornado appeared first on Google Earth Blog.

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China’s South–North Water Transfer Project

by Timothy Whitehead on Jul.14, 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 recently came across China’s South–North Water Transfer Project. China has more water in the south than the north and water shortages are becoming a problem in the north. The South–North Water Transfer Project uses canals to move water from large rivers in the south to northern provinces. The project consists of three main routes:

  • The Eastern Route that makes use of China’s ancient Grand Canal for some of its length and started operating in December 2013.
  • The Central Route that started operating in December 2014.
  • The Western Route that is still very much in the early planning stages.

With $79 billion already spent on the project by 2014 it is one of the most expensive engineering projects in the world.

We thought it was such a large project that a map of the routes would be easy to find, but surprisingly enough, the Wikipedia page is somewhat out of date and we couldn’t find any maps showing the completed routes. The best we could find were rough sketches drawn before the completion of the Eastern and Central routes.

We thought it would be interesting to trace the routes in Google Earth. We found the Central route without difficulty and it is easy to follow over its length of over a thousand kilometres. It is an enormous project, having to cross over or under major rivers along its route. It also goes through mountains with tunnels often several kilometres long.

The Central Route starts from the Danjiangkou Reservoir, which had to be raised by 13 metres, displacing some settlements along its shores.

before
after

 
Before and after of a settlement that had to be relocated because of the rising waters.

To get an idea of the scale of the project, this YouTube video shows some of the construction of the Central Route.

The Eastern Route was much harder to trace, as the area has a lot of waterways, including rivers and canals used for shipping and it is not easy to figure out which ones are also being used to move water to the north.

We also came across complicated junctions, such as this one:

 
According to Wikipedia the tunnel under the Yellow River consists of two 9.3 m diameter horizontal tunnels, positioned 70 m under the riverbed.

The tunnel under the Yellow River is nearly 5 km long.

You can see below the routes we were able to map out. We are not certain we have got all the Eastern Route sections correct and there are some gaps. The yellow sections are not navigable and are therefore definitely intended for moving water. The orange section is not part of the project, but is a section of the route of the Grand Canal, which extends further south than the water transfer project.

To see the routes in Google Earth download this KML file.

The post China’s South–North Water Transfer Project appeared first on Google Earth Blog.

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A further look at Chinese map offsets

by Timothy Whitehead on Aug.18, 2015, 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 talked about how the Street Maps of China are offset from the satellite imagery because of their laws requiring the use of the GCJ-02 datum. The GCJ-02 datum moves the map by different amounts in different places. You can typically work out correct coordinates by a simple addition or subtraction to latitude and longitude for a given area, but the amount to be added or subtracted varies across the country. So for a given city in China a particular set of offsets unique to that city would suffice for most purposes, but for countrywide mapping it is a lot more complicated.

We thought it would be interesting to get an overall view of how much the map is offset and in which direction. We found some Java code here to convert from WGS-84 to GCJ-02 and converted it to JavaScript for use in this post. We later found another version on Github that includes JavaScript code.

The first thing we did was to create this KML file that shows the relative magnitudes and directions of the offsets.


The smallest offsets are near Haixi (just left of centre), and the largest offsets are in the northeast of China.

Note that the magnitudes displayed above are relative. Actual magnitudes vary from a few metres to a few hundred metres and would not be visible at that scale.

Our next step was to create a converter to use with Google Earth. If you have a GPS track that uses the standard WGS-84 coordinates and you want it to match the Google Earth street map, then it might be useful. Just save it as a KML and use the converter below. It should work on most KML features, but ignores the camera position, but that shouldn’t matter for most applications. We make no guarantees regarding accuracy. The conversion is done in JavaScript and the file is never uploaded to our servers.

WGS-84 to GCJ-02 KML converter:

Convert to GCJ-02

We have also discovered that Baidu Maps uses yet another coordinate system called BD-09 that is based on GCJ-02 but adds further encryption. Baidu provides a converter to BD-09 as part of their API.

The post A further look at Chinese map offsets appeared first on Google Earth Blog.

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Chinese street maps out of alignment in Google Earth and Google Maps

by Timothy Whitehead on Aug.17, 2015, 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

While investigating the recent explosions in Tianjin, China, we noticed that the street map of China is out of alignment in both Google Earth and Google Maps. It is tempting to think that the explosions were so large that they shook the street map out of place (the largest, according to Wikipedia, has been estimated as equivalent to 21 tonnes of TNT). However, after a bit of research we have discovered that the street map offset is not new and is actually a result of old Chinese regulations from the cold war era.

It turns out that all maps that are legally created in China must use the GCJ-02 coordinate system, which according to Wikipedia, uses an encryption algorithm that offsets the map by different amounts for different locations. Google has followed the regulations and partnered with Chinese map provider AutoNavi to obtain the data and always shows the map data using the required GCJ-02 datum.

As we have mentioned in previous posts on censorship, countries can control and censor mapping information such as aerial imagery, 3D imagery and street maps that is gathered within their borders, but have little control over satellite imagery unless the company that supplies it operates from within their borders. As a result, both Google Earth and Google Maps do not show the satellite data using the offset GCJ-02 datum but stick with the standard WGS-84 datum used for the rest of the world. This results in the discrepancy we see between the street map and the satellite imagery. However, the Chinese version of Google Maps intended to be viewed from within China does comply with Chinese laws and uses the GCJ-02 datum for the satellite imagery as well. As a result, the street maps and satellite imagery line up nicely, but GPS coordinates will be offset. This is dealt with by Chinese navigation systems, which must convert between the datums to give the correct location on the map.


The China / Hong Kong border in Google Earth. The streets are out of alignment on the Chinese side, but correct on the Hong Kong side. The satellite imagery matches the latitude and longitude as produced by a standard GPS.


In the Chinese version of Google Maps, the situation is reversed. The streets are aligned with satellite imagery in China, but misaligned in Hong Kong. Both satellite imagery and street maps on the Chinese side do not match latitude and longitude as produced by a standard GPS.

Apparently Bing Maps and Apple Maps also follow Chinese regulations and use the GCJ-02 datum, whereas Open Street Map does not (and is thus illegal in China).

We also mentioned China’s strict mapping regulations back in 2006.

The post Chinese street maps out of alignment in Google Earth and Google Maps appeared first on Google Earth Blog.

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