Inverness supporters have no way to make the 300-mile round trip by public transport for the game on Sunday 2 February - but Doncaster told Sky Sports News Hibernian's home ground is the only practical venue.
"If you look at McDiarmid Park or Tannadice, based on this fixture last year which was a very well publicised fixture which did get a good attendance, those venues wouldn't have been big enough for the crowds involved," Doncaster said.
"Practically to have the two games in Edinburgh, given that Hampden Park is out of commission for a year with the Commonwealth Games, practically the two venues in Edinburgh were the only two viable solutions.
"Ultimately you have very few stadia you can use. Tannadice and McDiarmid aren't big enough for the crowds we hope will come to the games. We really were limited in terms of the venues we had to choose from.
"I think the Caley Thistle supporters have left with a better understanding of the challenges we face and why, actually, Easter Road and Tynecastle for these two games really were the only two realistically viable venues."
Caley Jags suporters group spokesman David Balfour said: "I am slightly disappointed in that neither the time, the date or the venue has been changed but realistically we could see the reasons for that. I think it is progress that we met with the SPFL and were able to put our concerns over."
The other semi-final - between Aberdeen and St Johnstone - will be held at Tynecastle Park on 1 February.