This map covers a lot of ground for the amount of habitable land and population. But this basin is roomy, distances are great and the geography is varied.
In some ways this is an extension of the Elven Highlands. It was settled by people from the Highlands in relatively recent times, when the Earth year was a positive number. For that reason there is no history section in this basin. The population is mainly Elf with a smattering of Troll and an ethnic group called the Monastics that are in the Megnor/Fmak/Tundrite family of races.
The culture is less hurried than the Highlands, people talk slower, walk slower and take more time with most tasks. They're not as much into showing off their bodies as in the Yakhan, but they are still beautiful and casual about nudity in most settings, but not in business offices. There is slightly more pair-bonding than is common in the Highlands, with about 80% of the people sharing a home with a full-time partner. That does not mean they are in exclusive marriages however. Most parties include sex, most people have multiple encounters per year and many have multiple per week. Sex clubs are generally more decorous than in the Highlands but there is a pretty lively professional sex scene. Those plying the trade are clean, attractive and reasonably priced. There is no stigma attached to being or consulting a prostitute and many are regarded as sex education instructors.
Music in the Dos basin ranges from melodic, mysterious and sensual to kick-up-your heels party music that would be considered 'bluegrass' by Centorins. The former is more often heard in the cities, the latter in the countryside, but both, and everything in between, are enjoyed in all parts of the basin. The reedy, crying sounds of the Monastics are still heard at times around Yarolin. More music is acoustic in this basin that the Highlands. Orchestras and chorales are common. Much of it is very cerebral.
Literature reaches its greatest heights in the Dos basin, not just on Kassidor, but in all of human space. Many novels are very philosophic. More titles are published here, per capita, than any other basin. There were basin-wide news publications using optical blinker code to transmit it from the very first settlement.
Learning is important to the people of Dos. Almost all children attend day schools. Every city has institutions of higher education and the city of Dos has a university complete enough to call itself Dos Kassikan. The literacy rate is just about 100%, even among the rural folk. That is much higher than the city of Kex.
Clothing is stylish and elegant. Women wear tops most of the time, always in business settings. The manufacturing of clothing is automated and the cost is modest. The climate varies greatly so the styles vary considerably from region to region.
Yaag is ubiquitous of course, but in this basin it is consumed with somewhat more moderation than the Highlands and nothing like the enthusiasm with which it is imbibed in basins like Zhlindu, Yondure or Borlunth. Harder drugs can be found, but they are less common than most regions of the planet. You can find something mind-blowing and/or addictive if you want, but you have to try. You do not need to be on your guard like in the Highlands, Trenst or Kshoned. The beer here is good, not too dark, but it will always be warm. Distilled alcohol is readily available but again, it is consumed with somewhat more moderation than some areas. Some of the aperitifs served at fine restaurants are especially tasty. Leelkozle (roughly translated as 'bat's milk') can be approximated at home with 50% Irish Creme, 35% Amoretto and 15% Southern Comfort.
People in this basin seem to make a sharp distinction between urban and rural. The urban places are a few big cities, the rural land is quite rural with only small market towns. Unlike the Highlands, there is not a large population of people living a lifestyle that is a little of each. Most people in this basin either farm and never take urban work, or live in a city and have no significant garden. Fewer people make the transition between the two life styles than in most basins.
Travel thruout the basin is comfortable but slow. There are no tubes anywhere but the city of Dos, but there is comfortable scheduled coach service everywhere and luxurious river boats connecting the major cities. If you travel by coach you will sleep in comfortable inns and eat good meals. The cuisine is a little more spare than in the Highlands but not what a Centorin palate would call bland by any means.
The far north of the basin is an extension of the Highlands. There is no clear boundary between them in culture, climate or scenery. As many people consider the city of Dysonuur to be in the Highlands as in the Dos basin. News magazines from both the Yakhan and Dos are equally available.
In the North Dos basin, the land where the Isanjaia and Khomein rivers run parallel to each other for a thousand miles, one is definitely in the Dos basin. News from the Yakhan falls off, people look to the city of Dos for their news, education and culture. Homes become more built and less grown. The clipped accents of the Yakhan fall away and there are less small cities. The land is rolling and the farms are larger than in the Highlands, though still tiny by Centorin standards, rarely more than 3 acres.
The city of Dos is the center of the basin. It is one of the most beautiful, affluent, cultured and easy-going cities on the planet with great music, fine arts, fine dining and a clean and well-run tube system. It is in the middle of the Dos escarpment, a region of beautiful rolling hills that surround the entire basin floor. The escarpment is the most scenic area in the basin but the hills are gentle enough that there is no call for mountaineering gear or anything of that nature. The five largest cities of the basin are in the escarpment (though Kwinarbec is nearly on the basin floor) and make full use of the water power available. The far east of the escarpment around Tathaic is the most rugged and has the most Troll in the population. The far west around Ensiltar is the gentlest countryside and the most Elf. Old Sindarin is spoken by many in that city.
The basin floor is relatively flat and averages two to three miles below sea level. The climate is pleasant in the summer, a bit cool in the winter when 61 Cygni is quiescent, but during an active spell, summer can be hot and winter pleasant. In this area you will find the most Monastics, but almost all of them are completely assimilated into the larger culture today. Less than a hundred miles east of Yarolin there is a surviving monastery and the forest villages around it have strong hints of their ancient culture. Other than that, the culture is very much like the Highlands, a little slower paced and without as much emphasis on the body. There is more plank and stone construction, but every village will have a public tap and probably some acoustic music around it. Most villages today have a public screen or two and data service is available. You will encounter no social resistence and even the country folk are educated enough to know of Centorin and the majority believe it is real. You can't get this far without speaking the language so you'll find intelligent conversation and you won't need to sleep alone unless you want to.
The vast polar prairie is nearly devoid of human habitation, though it's summers are no colder than the average day in Kex. Most of it is four or more miles below sea level barometrically and home to vast herds of prairie scamp, blanthettes and wooly thongga. There are theiropsoids of various species stalking them, and one should not venture out here unarmed. The distances are so great and the season so short that it is impossible to cross it in one year and if you are going any distance into it, you must be prepared for the winter. During mid-winter there are only a few hours of light per week and the temperatures hover around the freezing point most of the time.
In the Troll pass there is more prairie, but this region has much thinner air and the darks can get very frigid in winter. Just about all the wildlife in that area is from the scamp phylum, and there is not as much of it as on the polar plains. Once again, coriscamp can be dangerous so don't go unarmed.