In order to protect Vancouver's mountain and ocean views, the City of Vancouver established 27 so-called view cones back in 1989, which limit any development that may restrict these views.
An example of a view cone is pictured below, which shows the protected view of Grouse Mountain, as seen from middle of the Granville Street bridge.
The following map (click on it for a larger picture) shows some other view cones in Vancouver, with a specific reference to the proposed development at 1133 West Georgia street.
Interestingly, the developers of 1133 West Georgia had to revise their original plans, partly because they needed to fit their building within the designated view cone (the map below shows how the original design intruded upon the view cone).
In order to meet this requirement, Arthur Erickson and his fellow designers came up with the innovative 45 degree twisting motion of the new building. Similarly, the Shangri-La, which is located acrosss the street, has been designed with a triangular shape, in part because of the need to preserve the same view cone.
For more pictures of other Vancouver view cones, click here.
