Originally I had asked this on the Graphics Design SE but after some realization of the question I was asking, it's probably better to ask it here.
I'm making a fantasy world map in illustrator that I'd like to take to the next level by adding terrain contours. Currently, it's a flat political map like this map of Canada for example. I'd like to add an effect like what was used in this map here to show the relative depths of the water:
This is obviously not done by hand. They would have used a program that compiled real terrain data into vector contours which would get exported to Illustrator/Indesign/editor of choice. I don't have the luxury of real data, so how would I go about generating my own using the map I've already drawn as a starting point?
I have a good idea of what it is I need to do -- I'd like to export my existing map to a tool that will generate/edit terrain and then export it back as a vector for Illustrator. I'm just a total newb at GIS and don't have any idea of the software or tools of the trade. I've looked glancingly at things like R and Artificial Terrain Generation, and have used tools like QGIS in the past, but I could really use some direction on what's the best way to go about doing this and what software programs or libraries could help me.
I'm no stranger to coding and know C and Python pretty well. I'd appreciate any help I can get. Thanks!