What does 'とした’ mean in this sentence?


I'm looking for a bit of help understanding what とした means in this sentence
describing the UN flag:

> この旗は、真ん中に北極を中心 **とした** 世界地図が[描]{か}いてあります。

While I can get the gist of the meaning, can someone help explain exactly what
とした means here? I googled around a bit, but wasn't really able to figure it
out. Especially, it would be great to get an understanding of this grammatical
construction so I can use it / recognize it again.

Thanks in advance!




> 「A を B **と** する」

is a common set phrase meaning:

> "to regard A as B", "to assume A to be B", etc.

There is no "real and logical" center of the world possible on a two-
dimentional world map, agreed? Each world map, according to its purpose,
simply must regard someplace as the center.

(As a kid growing up in Japan, I never knew why our part of the world was
called the "Far East" because on the world maps used in Japan, Japan was
always located right in the middle. I was naturally shocked when I saw the
Western version of the world map for the first time.)

> 「この旗{はた}は、真{ま}ん中{なか}に北極{ほっきょく}を中心{ちゅうしん} **とした** 世界地図{せかいちず}が​描{か}​いてあります。」

On this particular map, the North Pole is in the center because that is what
they "decided" to place in the middle. It served its own purpose that way.

> "Right in the middle of this banner, a world map is drawn with the North
> Pole as its center."




> 「A を B **と** する」

is a common set phrase meaning:

> "to regard A as B", "to assume A to be B", etc.

There is no "real and logical" center of the world possible on a two-
dimentional world map, agreed? Each world map, according to its purpose,
simply must regard someplace as the center.

(As a kid growing up in Japan, I never knew why our part of the world was
called the "Far East" because on the world maps used in Japan, Japan was
always located right in the middle. I was naturally shocked when I saw the
Western version of the world map for the first time.)

> 「この旗{はた}は、真{ま}ん中{なか}に北極{ほっきょく}を中心{ちゅうしん} **とした** 世界地図{せかいちず}が​描{か}​いてあります。」

On this particular map, the North Pole is in the center because that is what
they "decided" to place in the middle. It served its own purpose that way.

> "Right in the middle of this banner, a world map is drawn with the North
> Pole as its center."

