I'm writing about a group of colonists on an Earthlike world, where I want to get the geography realistically correct, and it occurs to me that one thing I have not really seen discussed is the nature of the shoreline.
It actually matters to the colony what kind of shoreline they have, because if it's a beach, walking along it is many times easier than trekking through jungle.
So the setting is a world similar to Earth in the relevant ways, a continental shore (not a lake or inland sea, but shoreline directly exposed to the open ocean) with jungle inland, and from what I can remember seeing of various terrestrial locations, there are basically three types of shoreline:
Beach. This is the best case for the colonists; you can walk along the beach without having to scramble through jungle, so it serves as a highway.
Rocks. Jagged rocks, cliffs, fjords etc. You can look out at the sea, but it is much more difficult to move along the coast.
Mangroves. This is even worse than rocky cliffs; it's practically impossible to even reach the coast.
So what are the factors that determine which kind of coast will be present? Is there a realistic limit to how long a stretch of the continental coast will be beach?