This is a book a client brought in for repair/rebinding. They wanted to keep the existing book block as is, and have me put on a new cover. I said no, the pages need rehingeing and resewing before binding. The book will not function properly if the book block is just cased into new covers. Below you can see why-- someone, perhaps in the county clerk's office or a library where the maps were used, hinged all the pages with cloth tape and resewed the book as above. Part of the fault lies with the original printer. The grain on the paper runs contrary to the spine. 

It looks like the tape was too wet when applied, and/or the effects of humidity caused the paper to expand over time, but either way are restricted from expanding where the tape is, causing the heavy cockling. If the grain of the paper was parallel to the spine, it could have expanded properly and laid flat.  I'm thinking that the cloth tape should be removed, perhaps by laying the pages overnight between wet acid-free blotters to relax both the adhesive and the paper, and the hinges replaced with a Japanese-style paper, perhaps with the grain run parallel to the grain in the original sheets (anathema as that might seem). Below is a close-up of a hinge.