跟⋯⋯比
gēn …… bǐ
Expressing "compared with" using "gen"
跟…比起来 frames a whole comparison up front, then comments.
跟 + Noun 1 + 比(起来)，Noun 2 ⋯⋯
How it works
跟上海比，北京的冬天比较干 — compared with Shanghai, Beijing's winters are quite dry.
Unlike a 比 sentence, this one allows 很, 比较 and 非常 in the comment, because the comparison is set aside in the opening phrase.
和…相比 is the written equivalent.
Examples
gēn shàng hǎi bǐ, běi jīng de dōng tiān bǐ jiào gān
跟上海比，北京的冬天比较干。
Compared with Shanghai, Beijing's winters are quite dry.
gēn qù nián bǐ qǐ lái, jīn nián hǎo duō le
跟去年比起来，今年好多了。
Compared with last year, this year is much better.
gēn tā bǐ, wǒ chà dé yuǎn
跟他比，我差得远。
Compared with him, I'm nowhere near.