To find how many cities are on the coast of california, you would reference a

In order to achieve this, you would have to use modern day tools such as Google Earth, which not only gives you a geographic view of the Coast of California but also give you a "map view" in which you can see all of the urban locations along the coast of California. Another helpful feature of this tool is that it can let you see the current state of the location you are watching.  

d. migration of french settlers into english colonies

"germany's geographic location was an advantage when it was on the offensive in the war because it was situated next to an extremely wide river, the rhine, which was difficult for the allies to cross."