What do the different coloured dots mean?

Question

While playing Fire Emblem, I noticed that there are places on the map that are different coloured dots. There are red and green and purple ones, along with the more normal white ones. What is the meaning of the different colours?

Answer 1

There are a few different colors on the map. @gorogoro got most of it right.

• White dots are completed story maps, and allow you to buy items from them, as long as a random encounter isn't there. If a Merchant is there, the selection is expanded the first time you shop there, with an item or two being on sale. The discount depends on the item (ie. Master Seals only get 9%, while Iron weapons can get close to 20%). You can also encounter random Risen battles here, and their difficulty is directly relative to what the story levels were. ie. A random encounter at Ylisse will be significantly easier than one encountered at Ferox Arena, or further in the story. If you fight a random battle at a spot that has both a Merchant and a Risen, the Merchant will be on the map. Saving them grants you a free random item.
• Red dots are the next story mission. There should only be one of these available at a time (unless the path splits, and I haven't reached that yet).
• The single purple dot is the DLC spot.
• Green dots are the Paralogue mission. These are extra, optional missions that you can choose to undertake, and get unlocked at certain points in the story. Essentially side quests. Some will reward you with extra characters (Paralogue 1 & 4), while some just expand the story, and provide extra experience and items.
• Orange dots are maps gained from SpotPass. These are added to specific areas on the map, and you have to be far enough in the story to challenge them. You can unlock them before you can challenge them, and they will sit there until you get far enough in the story. They seem to be extra missions, just like Paralogue ones, so they might reward you with the same things.

Answer 2

1. White dots: Main story battles that you have completed
2. Red dots: The next stop in the main story.
3. Green dots: A series of maps that can only be unlocked after completing certain chapters (I don't know if I can explain more because it's quite spoilerific, but you can access the first one after Chapter 13). Streetpass maps also uses the green dots. You can recruit extra units in these maps.
4. Purple dots: Random Risen battles where you will get bullions for clearing them (it appears randomly from time to time).
5. There is also the orange dot which are bonus maps you can get via Spotpass, you can only access them after you have completed the 2nd last chapter though.