Vegetation, Climate, Ecology, and Pollution

[Gary Thomas]

There are more types of easy-go-throughs than mountain passes. A plain between forests is a pass. A hill between mountains is a pass. A valley between plains is a pass. A snow-free route is a pass. It just depends on the circumstances, i.e. the surrounding squares. Most routes and roads will go through the pass, so its clear where it is.

It will not be clear if the road or route has not been established. While a road automatically implies a pass, the converse is not the case. Hannibal did not use a road to cross the Alps. And there are degrees of passes, ones that climb a high col are different from ones that follow a river gorge.

The "surrounding squares" are 50km away, and do not bear on local conditions.

Cheers

[Simon Loverix]

It's just this, when you scout a 10000 km² area well enough, you will always find a pass. fe the Alps: almost every square should be a pass then fe St Gotthard pass, Brenner pass,
..
And a f.e. snowed, young mountain range is always dangerous to cross, with or without pass. The risk will still depend mostly on the actual terrain.
I like the idea, but there will also be trouble when a pass is generated in the middle of a mountain range. Ideally, we should limit it as a connection between two low squares and not allow several passes next to each other.
It's something similar to channels.

[Gary Thomas]

The Himalayas, and the Southern Alps (New Zealand) have areas where there are no passes in 100km.

I would regard such areas as essentially impassable. I would also expect "passable" mountains to join more normal terrain (on opposite sides of the mountain range).

My main point is that some of the most interesting battles have occurred around defending passes (Thermopylae for example). These are different in kind from defending straight out mountain terrain.

Having a 100km wide gap in the mountains to allow passage is a bit extreme and no fun!

Cheers

[Mark_Everson]

I basically support Gary's take on this. Mountain squares without passes should be essentially impassable. One alternative would be to have two types of mountain tiles: passable and impassable. Passable would be the ones that infantry could with great effort cross in any direction. Impassable would be like the Himalayas where you can only cross with infantry if there is a designated pass.

[Lord God Jinnai]

I would qualify that with a certain technological level. It could be possible with modern technology to have infantry cross mountains w/o passes such as in the Himalayas, but it would be difficult with a lot of men lossed, though not impossible.

[Gary Thomas]

Although I suppose it would be possible for troops to cross an "impassable" mountain range on foot using modern technology, I cannot image any situation, except possibly a rout, in which they would do so. They would almost certainly airlift over the mountains.

Cheers

[Simon Loverix]

The strategic possibilities make it worthwile indeed. The terrain in general should be difficult to pass then, to make that pass important.
And would it be recorded
-as a special, or
-as a distinct terrain type (impassable mountain, passable mountain, hills, R, P, D) or
-do we consider the terrain type mountain as impassable and the tt hills as passable?

[Gary Thomas]

Passes through any obstructing terrain are always militarily interesting. My own preference would be to treat a pass like a river, giving a relatively easy route through otherwise difficult terrain. It would not be necessary to provide all the possible cobinations, including branches. Passes joining NW and SE or SW and NE would, I would think, suffice.

The characteristics of the underlying terrain and of the pass would remain distinct. The defensive value and the economic contribution would be that of the underlying terrain.

Cheers

[Lord God Jinnai]

I'd say treat passes like unexplored rivers then. If it's your civs first time through the area, they shouldn't get a pass bonus. After that they should get a certain % chance to find it every time they enter that square.

[Gary Thomas]

I would expect that anything unexplored wouldn't get a movement bonus. In the case of a pass, apart from the possibility of locals telling you about it, it could be quite a while before it is found.

Cheers

[Gary Thomas]

I have reread Simon's rather magnificent ecology proposal, and would like, generally, to follow it in the coding. Although I am not immediately concerned with the full model, I am concerned with the appearance and movement characteristics of the terrain, in order to tune up the GUI for D5. In line with this, none of the finer details will be included.

One of the things that will never, in my opinion, be relevant to the game is the possibility of partial terrain squares: 50% plain, 50% mountain. On the other hand, I feel that mixed cover (50% forest, 50% pasture) will play a very important part in the system.

One of the big principles of object-oriented design is orthogonality. In this context (as, in fact, in mathematics) this means attempting to separate things as much as possible. As I confess I am over- fond of saying, "minimize the dependencies".

For this reason, I believe the following characteristics of the geographical elements of terrain should be dealt with separately.

1. Landform. This is the physical shape of the land. The categories I propose are: flat, rolling, broken, massif. Visible on map.
2. Material. What the land is made of: soil, sand, rock. Visible on map, unless covered.
3. Altitude. In metres, rounded to 100.
4. Landcover. None, crops, pasture, scrub, forest, jungle. Visible on map.
5. Climate. As specified by Simon. Not visible on map.
6. Watertable. As far as my purposes are concerned, this affects low altitude flat land only, producing swamps which are visible.

Linear features can be superimposed. Natural ones:

6. Rivers. Described in more detail below.
7. Lakes.

Human generated linear features:

8. Roads.
9. Railroads.
10. Canals.

Other humans artifacts:

11. Urban areas.

There may be other things indicated later (mining areas for example).

All of this gives a reasonably easily implemented plan for D5, though perhaps not every detail will be there for D5.

I do have one problem. The consensus, and to some extent the reasoning, indicate that rivers should run through the middle of squares. I believe I was a lone voice in the wilderness arguing for rivers between squares (based essentially on the argument that rivers 100 km apart are very BIG rivers - there will be lots of smaller, invisible, rivers in the square). Also roads run through the middle of the square.

Which should be drawn on top? Or should they be offset, with the result that a road is always on the west (or east) side of the river?

There is a related area to be considered. On the scale of the map, if there are any roads at all they will cover the whole square, connecting every microsquare to its neighbours. Anything important enough to be the only road shown will be different in kind. In view of this, I might propose a category of "roaded" which makes movement in the square easier, and is perhaps visible as a grid on the square. Alternatively we could use the Civ2 method and have a little x in the middle of a square to show that it has roads, and connect it to any adjacent square that has roads. This has the advantage that a road (in a square) does not have to have a destination.

The situation for rivers is different. Two rivers flowing side by side (the Tigris and Euphrates for example) are not connected at every point simply because they are in adjacent squares. Thus each river "segment" in a square needs a destination (or direction), and there may be four such segments (or eight if diagonal rivers are allowed - if they are, someone else can code it) per square. Of course if the rivers were between squares...

I would appreciate some comments on these matters, particulary from Simon (if he is listening...).

Cheers

[Mark_Everson]

Hey Gary, I agree with your basic take on this, and will only respond to a few things...

Which should be drawn on top? [Rivers or roads] Or should they be offset, with the result that a road is always on the west (or east) side of the river?

Good point, I hadn't thought about that! Just to make life easy when road / river segments are drawn we can just use a favored orientation. FE road is always slightly clockwise to river. But we need to have examples for the graphics to really see if this can work. For D5 I'd say just use whatever is easiest, even if it may be ugly.

There is a related area to be considered. On the scale of the map, if there are any roads at all they will cover the whole square, connecting every microsquare to its neighbours...

My intention was to only show major roads. Minor roads would only be an economic infrastructure category (or rolled into other infra) If we desire we could show "local road density" but generally this will just correlate with urbanization level anyway. So I would prefer to defer the minor roads discussion till later.

The situation for rivers is different. Two rivers flowing side by side (the Tigris and Euphrates for example) are not connected at every point simply because they are in adjacent squares. Thus each river "segment" in a square needs a destination (or direction), and there may be four such segments (or eight if diagonal rivers are allowed - if they are, someone else can code it) per square. Of course if the rivers were between squares...

IMO roads and rivers should be constructed in segments as you say. All segments go from the center of the square to a vertex or middle of an edge, making 8 possible road (or river) segments in a square. Usually there will be none, or two (a road or river passing through the square center, on segment in, one out). But this approach does allow for roads to be built in almost any manner the player might desire. Rivers, as you say, also need a direction, at least if the other models will result in flow direction making a difference to the player.

On a related note... generally a player will just build a road with a mouse-drawn line to indicate where the road goes, and an allocation of resources to build it. None of this pushing settlers around crap for our players!

[Gary Thomas]

On a related note... generally a player will just build a road with a mouse-drawn line to indicate where the road goes, and an allocation of resources to build it. None of this pushing settlers around crap for our players!

Actually that is how Call to Power does it.

Cheers

[LDiCesare]

Cross-posting from movement units thread:
Do we have primary terrain type/subtype and secondary terrain with figures explaining to what extent you are of a given kind?
e.g.
Terrain is flat (90%) rolling(10%), with no cover (50%), crops (50%), roads (5%) no roads (95%), dry (99%) wet (1%).
I think Gary said something like this a little earlier, although I can't see why the main terrain type cpuldn't be mixed (plains-rolling would be OK, not plains-mountain, though).
The types currently covered in Gary's code are:
flat to mountain
cover
soil type
wet/dry
To which I'd add
road/no road.
Roads are infrastructure, though, so is there any other kind of infrastructure that would need to be modeled the same way? (Fortresses maybe)
What about rivers? Are they just "wet"?

[Simon Loverix]

I strongly advocate for minimally mixed terrain.
Only this:
% natural/ % in human use
The percentage in human use could be further split up into farmland and infrastructure (i.e. buildings), depending on the number of units of infrastructure, when it was needed.