The Russian parliament is currently discussing a new law that will establish an autonomous internet in Russia. The network will no longer depend on servers and services hosted in other countries.

The U.S. dislikes that as shutting down Russia's internet by manipulating servers in the U.S. will no longer be an option. Spying on Russian internet traffic will also become more difficult.

The usual 'liberals' in Russia were told to raise some protest against the planned move. The BBC reports:

Thousands of people in Russia have protested against plans to introduce tighter restrictions on the internet.

A mass rally in Moscow and similar demonstrations in two other cities were called after parliament backed the controversial bill last month.

The government says the bill, which allows it to isolate Russia's internet service from the rest of the world, will improve cyber-security.

But campaigners say it is an attempt to increase censorship and stifle dissent.

Activists say more than 15,000 people gathered in Moscow on Sunday, which is double the estimate given by the police.

Reuters gives slightly different numbers:

The rally gathered around 15,300 people, according to White Counter, an NGO that counts participants at rallies. Moscow police put the numbers at 6,500.

Reports of crowd numbers are used for propaganda purposes and often false. On February 22 the British oligarch Richard Brenson organized a concert in Cucuta, Colombia. While "authorities" in Colombia claimed that there were "over 400,000 people in attendance", Vice News reported more than 300,000 and the Washington Post wrote that 200,000 were there. By using aerial pictures and scientific crowd density measurements we proved that less than 20,000 people attended the concert. Following that the Washington Post silently deleted its 200,000 claim.

The BBC provides two pictures with its piece.

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Note that both are relatively tight front shots of the demonstration. It is impossible to check a crowd size from frontal pictures. Professor of Crowd Science at Manchester Metropolitan University G. Keith Still notes about density estimates that:

Density can appear higher with lower CCTV angles

That such frontal pictures are very misleading was demonstrated in 2015 when photos revealed how a small number of hypocrites abused a large memorial march they did not take part in for a photo-op.

Here now is an aerial picture of the "mass rally" in Moscow.

via Russian Perspective - bigger

That picture allows for a quite accurate crowd estimate. The width of an arterial road lane is 3.3 to 3.6 meters (11-12 feet). The street in the picture has ten lanes plus a medial strip of 1 meter. The total front of the demonstration is thus 37 meters. One can use the comparison to the lane width to measure the depth of the crowd. Detail picture analysis shows a medium dense crowd in the first 7 meters from the front with about 2.5 people per square meter and a light to medium density of 1.5 people per square meter for the next seven meter. The number of people beyond that are probably some 300 in total.

We can thus calculate:

37m * 7m * 2.5 ppl/m² + 37m * 7m * 1.5 ppl/m² + 300 ppl = 1.336 people

Even if we assume a high density of 3.5 ppl/m² in the front zone, 2.5 ppl/m² in the zone behind them, and 500 people mingling in the rear area the total is only 2,054 people. The city of Moscow has a population of 17 million with another three million in the suburbs around it. 2,000 protesters are 0.01% of its population. One would have to triple the density to even reach the police estimate of 6.500 participants or 0.0325% of the people living in Moscow.

Neither the police estimate nor the much higher estimate of the White Counter 'NGO' that Reuters quotes are consistent with the picture. According to a 2014 blog post atirevolutions.org "White Counter" was created in Russia:

in order to counter government figures on the number of protestors who join demonstrations. As is typical, the Kremlin will always downplay the numbers.

In this case the Kremlin seems to have tripled the attendance number. Is Putin somehow against the new law?