Whose, ..... why?

There are many instances such as:

The Hawai'i Convention Center is a world-class facility WHICH PURPOSE is to draw
new dollars into the economy and to increase tax revenues for the State...

in which which seem to mean whose. can anyone explain to why.

That's just incorrect.

The Hawai'i Convention Center is a world-class facility constructed for the purpose of drawing

new dollars into the economy and increasing tax revenues for the State... Or

The Hawai'i Convention Center is a world-class facility constructed to draw new dollars into the economy and to increase tax revenues for the State...