Createspace do different sizes of books and as your illustrations are b/w you can publish your book at a similar price to VOSP, no upfront costs, only a proof copy which costs the price of one book and as author/artist you can buy your books at nearly a third of the retail price. Your illustrations in VOSP are printed really nice quality. All I did was embed them in a word processing doc (OpenOffice.org) and exported from there to pdf. Then you upload to Createspace and order your proof. VOSP has a full colour cover. Your map is scintillating!