Any sufficiently advanced magic is indistinguishable from technology.
I could use some advice from an author who has experience making maps for their worlds, but anyone is free to add their opinion.
With my resent idea (Actually an idea I've had for awhile now, but finally got an idea about how it happened) about the plot of my story it has become conflicting with my map. Well if anyone can understand this..... The worlds history is (similar to/the same as) ours-> distant future, hi-tech-> an event/apocalypse-> civilization destroyed, some humans survived-> the world is recovering, magic discovered-> the story's present day.
So, basically what would be very hi-tech/distant future to us has passed and faded to a forgotten myth.
Now for my dilemma, if I use this in my story there would probably be ruins and left over changes to the landscape roads, dams, canals, etc.
Should I make major changes to my map, make a new one, use a real map, or just scrap the whole idea?
In my opinion, the map is subordinate to the story. It is a tool to help you to tell the story, either by helping you to communicate with your audience or by helping your to better understand your own world. If it doesn't serve that purpose, it needs to be modified, abandoned or redone to suit.
When getting down to the specifics, though, consider how much time has passed since the collapse. If this world has crawled back out of the stone age all the way to a new Industrial Revolution, we could be talking in terms of millenia. Not much of our modern world (and I would assume the greener, more organic future world) is likely to survive more than a few centuries. We don't build to last these days. In addition, the massive quantities of resources available in a city or along a highway would ensure that those structures would be used as quarries and mines, further reducing their mark on the land.
On the other hand, if civilization rose faster this time around because people could reverse-engineer tech from what was left behind, then you'll definitely see more signs of the older world.
Another thing to consider is that the settlements of the old world are probably located in places where it is natural for a settlement to exist. Las Vegas notwithstanding. So the new civilizations are fairly likely to go ahead and build on top of the old cities. They will probably appropriate the old roads, since they're already there and already lead to useful places. So your existing map may well show the same features and need only minor adjustments.
If you intend to set the story in a specific modern geographical area, though, then you'll probably need to start from scratch in order to get the landforms and general settlement locations to line up.
Bryan Ray, visual effects artist
I wouldn't necessarily panic about changes or things being absent however. On top of Midgardsormr's great points, bear in mind that a map is not a satellite photograph. Even when it's a "satellite map" it's still not a photograph of the world, because, to begin with, if you look at actual satellite maps you can't see roads, rivers (except very large ones), or even towns (you can generally see big cities!). You're adding data, and it's selective (you don't show every single tributary stream on a regional map!). A map only shows what's important to the people who are going to use it. If ruins of 20th Century cities aren't important to the society of your book, they're not going to put them on their map.
My story definitely comes first, the map is for me to see where certain things are. (Its hard to make maps of mostly unexplored territory and deadly to explore it, so any maps shown in my comic will be incomplete.)
You can also go the route of the early map makers who have made maps based on peoples assumptions of what is there. There are quite a few early maps of North America where the lay of the land makes NO sense at all now that we what is where. Of course this does not help the author at all except to know what sort of legends there may be about a certain area. A sort of "Here Be Dragons!!" kinda thing...
Art Critic = Someone with the Eye of an Artist, Words of a Bard, and the Talent of a Rock.
Please take my critiques as someone who Wishes he had the Talent
I've seen one of those for North America on TV, the one where California was an island.
wow this is awesome!@