4 days ago a video showing 3-400 detainees handcuffed & blindfolded at a train station in Xinjiang was uploaded to YouTube ()
In this thread I'll share how I've verified that this video was filmed at 库尔勒西站 (41.8202, 86.0176) on or around August 18th.

Firstly, let's look at the video. It shows a screen recording of a dji drone which has captured hundreds of detainees (presumably Uyghurs) being led off of a train, and lined up - freshly shaven, blindfolded and handcuffed - at a train station.

In terms of information to verify this video, it is quite scant. The title mentions that it shows something in Xinjiang, and the description says that it was 'taken in China' - "这些视频是在中国拍的", which is not a lot to work with.

Moreover, this is the only video uploaded to a new account, but let's look at what there is available for us to geolocate: building, cell-tower, blue buildings, carpark, trees, train tracks ect.

The biggest clue is the orientation map in the bottom left that says (after a bit of squinting & checking Baidu Maps) "巴音郭楞蒙 古自治州", an autonomous prefecture in Xinjiang that is often largely synonymous with the city of Korla. This was clearly filmed to the NW of there.

The drone's FPV camera is also pointing almost straight down the train tracks, which shows the orientation of the tracks at about 282° if you measure it. This narrows down the section of train tracks that it could potentially be.

The bigger clue lies in the 10km scale bar in the bottom left, which (on my screenshot) represents 6.48cm. The distance from the approx centre of Bayingol label to the location is 8.05cm (at a bearing of ~ 300°)
(8.05/6.48)*10 = 12.42km at a bearing of 300° from the label.

Feeding that into Google Earth gets you pretty bang on. You can see the building, the trees, the tracks, the car-park (which was in the process of being paved in the June 17th 2019 satellite image - important later!)

Indeed, just look at this. It's pretty clear where this video was taken (also just want to shout out to the Chinese script were the exact point of the label could be determined because each character is a square).

Now, to work out when this video was taken. Luckily the world is full of little sundials. See this telegraph pole. It casts a shadow which is conveniently clear, ending about 8 white lines away from the pavement, and in line with (or ~ a foot past) where the stripes get shorter.

This puts the shadow's end at about exactly this position. The image in Google's collection where the shadow looks the closest is taken on 7th Sept 2019. Regardless we can show that the shadow is approx 5m long with a sun azimuth of 173.38°. This are all very approximate.

Now to reverse engineer how tall the pole is. The Google imagery shows a the pole's shadow at ~6.75m long.
Looking in Digital Globe's catalogue we can also see the sun elevation was 52.8°. Feeding that into SunCalc we see that at that time an object 1m tall casts a 0.76m shadow.

6.75*(1/0.76) = 8.88
Therefore we know that the pole is ~8.88m tall.
All we have to do to find an approximate date is play around with SunCalc ( http://www.suncalc.org ) and find the time/day where an 8.88m object casts a 5m shadow with a sun azimuth of 173.4°

12:06pm, Aug 20th

These figures are approximate! You'll notice it changed from August 18th to August 20th, that's because when I re-did it for this thread it must have been measured differently by a few feet or degrees. This is impossible to avoid when youre measuring so fine with less detail.

The year is a trickier thing to determine, which has to be done through chronolocating the video with satellite imagery - matching and picking the difference between the video and various satellite images. In this video the carpark is not paved. It was being paved in June 2019.

This rules out August 20th 2019 as the date of the video (also the red-and-white stripey path was repaved green for some reason - it's remained green, not just covered for the nearby paving). The crackdown started 2017, so with context it is either Aug 2017 or 2018.

There aren't a lot of further clues, but the world does always change! So the best I could find are these two small bottom most bushes. In 2017 they weren't there. In 2018 they were. Therefore we can tell this video was filmed on/around August 20th 2018.

I should have mentioned the year in the first tweet of this thread, sorry, but I hadn't worked it out by then! Silly me just assumed it was 2019. This is why it pays off to check!

But essentially this thread offers some techniques to verify imagery that I hope you find helpful.
By verifying it, you can essentially prove that it is real and true, that what you're seeing did occur, and that it's location and date is known with enough detail to make it useful

International warrants have been granted to prosecutors on the basis of social media videos which have been verified in such a manner. https://www.bellingcat.com/news/mena/2017/09/04/geolocating-libyas-social-media-executioner/

It also fact checks the video, so that media organisations can be comfortable sharing it to their audiences.

one important thing I totally forgot to mention! and thank you @il_kanguru for reminding me! The sun is essentially in an identical position on the other side of the equinox, in this case April 22nd. The position of the sun can't tell you if it's Aug 20 or Apr 22

Since this has blown up (thanks everyone! the more exposure this video gets the better!) overnight, I might add a bit more context that I avoided mentioning last night as it is speculation, but the next few tweets might be helpful in getting an idea of what that video shows.

Firstly, there are A LOT of areas built for detention in Xinjiang. Here are 150 centres from my collection so far, this also excludes most prisons.

Theyre not all created equal, broadly what I've heard and seen suggests there is 4 levels of detention. These range from 'light re-education & forced labour' to 'proper prison sentences'. Where you get sent is often at the whim of local administrators and their quotas & is fluid.

The lightest of these facilities seem to be the stream that you have heard of people being released from this year. They're generally fully enclosed facilities, but somewhat similar to dormitories, where detainees are given an intensive 'education' in the 12 socialist values.

Up until last year these facilities were normally more highly securitised with high fencing keeping detainees from moving around at all. Recently facilities in this LOWEST security have removed the worst of that fencing.

They are also often directly attached to factories, ostensibly to 'vocationally train' detainees, however when many of the detainees here are nurses or school teachers, they really dont need to be taught to sew for 9 months.

People in this level of detention are also generally allowed home on a Saturday night - though some of the more remote facilities have cut that privilege because the buses cost them too much.

In the last 12 months or so we've started to hear reports that detainees from the first wave of the crackdown have started to 'graduate'. This is generally them being released under village or neighbourhood arrest or being sent to huge factory/coerced labour complex such as below

Those people which havent graduated remain in those camps, but as they have been de-securitised to some degree, MANY detainees have begun to be transferred to higher-security tiers of the system, often including being formally sentenced to prison.

The next level up appears to also be for re-education, with the stated intention of 'rehabilitating' those seized with the evils of radicalistation (which includes fasting or praying), but are much higher security facilities with most buildings surrounded by fencing & walls.

These facilities don't seem to grant any privileges to the detainees who cannot leave except to nearby factories for their vocational training, but in this stage the idea appears to be far more ideological brainwashing/language teaching than vocational training.

Next, there are the 3rd tier of detention, these seem to essentially be prisons but for people not formally charged. In these places the focus doesn't seem to be any however-perverse idea of rehabilitation, but more to just remove people from the population. They look gnarly af.

Needless to say, with 6 high barbed wire fences and a huge concrete wall standing between any detainee and any of the outside world, detainees in these facilities don't get out much for anything.

Finally there are your classic prisons, where those sentenced live out years of pre-trial detention and then far longer in their prison sentences. Prior to the 2017 crackdown, prisons in Xinjiang looked like the first photo here, now they look like the last two.

For a non-satellite perspective of what these four tiers actually mean. This famous photo probably came from a 2nd tier facility - the higher security re-education facility. This isn't even as bad as it probably gets in prisons or 3rd tier prison-like facilities.

To bring this back to the original video, the detainees there were going from the relatively small Kashgar Detention Centre (first picture) to the much more expansive Korla facilities (red squares = prisons).

Kashgar has extensive re-education facilities but extremely limited detention facilities, the facility shown in the last tweet is the largest prison they have. Therefore it makes perfect sense that detainees are regularly transferred out of Kashgar to larger detention facilities.

Last year, I published a report with @fryan and @DaniellesCave for @ASPI_ICPC which looked at the physical growth of 28 camps. Please give it a look here. https://www.aspi.org.au/report/mapping-xinjiangs-re-education-camps
Since then we've learnt a lot more about the system, and expect more reports on it soon!

This thread is rightfully getting renewed attention, so I should correct the record here, that now I believe the video was filmed in late April 2019, based on surrounding vegetation and the cargo-yard in the background.
There was far less cargo in August 2018.