cities-skylines
I am fairly new to Cities Skylines and not a heavy gamer. I cannot figure out what functional role, if any, canals play. Are they purely aesthetic, or do they change how the game works in some way? Can I use them to build a city which works better, not just looks better? If yes, how?
Small boats aren't available in the game and it doesn't look like ocean liners would fit in there.
I have the After Dark expansion, but no other DLC.
After some testing myself, I discovered this message means your industries are lacking one or more of your basic services such as fire protection, police, mass transit, etc. Placing offices near polluting industries can cause the "Too few services" message because of low land value. What the message actually is saying is: there is something undesirable about coverage or the location. In my case it was fire:
This was my fire coverage before I added a fire station.
And this is after. The messages all disappeared within a few seconds. If you are getting this message, be sure to check all your overlays to see what they are lacking!
Districts can be used for a couple of different purposes. Probably the most important trait you can set is the "no heavy traffic" policy. This can be extremely useful if, eg, you create a residential district which would be technically faster to use to go between your industrial and commercial sectors, but you want to have your trucks use the longer freeway that is better equipped to handle traffic and won't complain about the noise. You can also use this to create "no truck left turn" intersections by creating a small district on the left side that doesn't allow heavy traffic.
Other than that, there are more ways to use district specialization. JMR mentioned that you can use the lower electricity or water reduction policies in specialized industry districts (electric can be a net positive in office and high commercial areas as well if I recall). Generally, you'll probably just want to use Parks and Rec and recycling as general city policies, but if you really are pinching pennies you can restrict those to certain districts as well. People will require better land value in high tax areas and won't care as much in low tax areas, I probably don't need to explain why that's useful to set by district.
Another important (if callous) thing you'll need to do later on, once you have a well-educated population, is to create low tax, high density residential areas with no access to education past elementary school so you keep a supply of poorly educated citizens to man your industrial areas. In those areas using the education boost policy is obviously not wanted.
Should you combine different zone types (residential, commerce, industry) into a common district or is there a benefit of keeping different zones in different districts?
This is situational - in general, it probably won't make much of a difference if you combine different zoning types into the same district since most policies are separated by zoning type anyway (taxes, business investment/High Tech Housing), but if you want to optimize the reduced usage policies you should keep them separate (that said, once you get past 20000 people or so money becomes a non-issue).
Best Answer
Canals have a variety of purposes from aesthetic to functional. Some players make like having canals run through their cities for looks while others may use them to direct sewage to certain areas.
Directing sewage to another area is both aesthetic and functional since sewage affects cim health and reduce land value.
Do not, however, make a canal for only sewage that does not connect to a water source. That will overflow and cause flooding over time. Bodies of water in the game have water sources that add water if it is below a value and removes it when above.