This infographic shows the history of the development of the Apple iPad, from its launch only two years ago, to the birth of the third-generation iPad yesterday. It explains the changing iPad specification, the success of the iPad, and how each generation of the iPad differs from the last. See also: Apple new iPad vs iPad 2 comparison review.

Apple began taking orders for the first generation iPad - from US customers only – only as recently as on March 12 2010. Given that the iPad was a reboot of the moribund tablet market, at the time it seemed staggering that 300,000 iPads were sold on the first day the iPad was available. (Particularly given the lukewarm reception HP and Microsoft's attempt to reboot the tablet world had received earlier that year at CES.)

But sold those iPads were, and so began a remarkable success story that reached stage three yesterday, when Apple announced its new iPad to a waiting world. This infographic, produced by internet marketing agency Elevate Local, shows how the iPad has developed over the past two years.

It details in graphical form the sale of 15 million first generation iPads before the iPad 2 launched, and how the second generation iPad built on and expanded that success, and led on to the new iPad (see New iPad review). More importantly, it details the way in which the specification has developed over that time, so that we now have an HD iPad with dual-core processor, 4G connectivity and that amazing screen.

The way that the iPad specification has developed over three generations is remarkable, shown here in graphic form.

The evolution of the iPad