是……的 construction without 的?
Rephrase it a bit and you can get the 是……的 construction.


我來(的)是要瞭解這一個區的市場情況。
我是要瞭解這一個區的市場情況來的。


I wouldn't phrase this sentence using the 是……的 construction though, the detail 要瞭解這一個區的市場情況 is a bit long, plus it contains another 的 inside the detail, making it more easily misunderstood.