Calgary has traditionally had three main offenders.
1) the blocks at the north end of downtown ( a decade ago the white topped towers didn't exist, so there were 3 1/2 full city blocks of parking lots all together).
https://maps.google.com/maps?q=calga...a,+Canada&z=18
Thankfully, as if a few weeks ago all of the empty lots you see have plans to develop
2) the lots around the tracks at the south end of downtown
https://maps.google.com/maps?q=calga...a,+Canada&z=16
This is former rail industrial land that is only being developed at a glacial pace
3) The East Village
https://maps.google.com/maps?q=calga...a,+Canada&z=17
Many of the vacant blocks which don't have cars in this view did a few years ago.
Luckily the city has been working on developing the entire area, with planned or in progress projects being several towers, a new central library, and the National Music Centre. Every lot here is expected to be developed in the new couple or few decades.
So really #2 is the one shameful area without a lot of plans.