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**Lord God Jinnai** · April 2, 2000, 14:53

Geology would also affect the type of forest. Higher elevations and in artic regions Pine forests replace deciduous forest completley while in the middle its mixed.

On randomness do to pollution I'm all for it, except we should have some sort of trend because in the game the scientists will be discovering this and trying to find ways to prevent it.

One other thing is that we know that these gasses do cause warming. There have been theories about it causing ice agaes since near its infancy of the greenhouse effect theory. Anyway because volcanoes produce the same type of pollutants we also have to remember that they also affect things, not just humans.

Also with just random things happening you won't have any long-term implications to worry about, just short term. This gives the message to the player that whatever they do the idivisual effects won't last long and can be corrected (FE if a swamp is created you can drain the swamp).

I do think a poll might help though if TK wents to do one.

**Richard Bruns** · April 2, 2000, 14:56

I should note that the border checking is only meant to determine changes between the five base terrain types. Forests can grow anywhere within the last three terrain types. So forest growth can be checked for in random chunks of the map. These could be 3x3 blocks, 5x2 blocks, or whatever will go fast while looking natural. If certain conditions are met, the forest cover in that grid could go up or down. So, assume that the region checked contains basic savannah and sparse forest. If the test showed forest growth, the savannah would become sparse forest and the sparse forest would become a basic forest.

**Lord God Jinnai** · April 2, 2000, 16:27

It is usually easier to downgrade land from forests to non-forest types than to reverse the trend.

**alms66** · April 2, 2000, 17:31

Richard,

You've got some really good ideas about the different types of terrain and their changes. Blocks are probably a good way to handle those changes, but I don't know what a good size would be, 5x2 sounds o.k. though.

There was some discussion in the old map generator model thread about half way down, it was mostly mining, but could be used for the deforestation rules also. There was also a little discussion about having more terrain types, about a quarter way down. Mark had mentioned putting that off until later because it would be an easy add-on.

Richard & LGJ
Global Warming: Well, i really didn't mean for this to get in here but anyway... I think we can all be happy with random problems arrising through global warming, we've established that.

So how about we use the death rate increases & terrain changes for the random stuff. And track the avg temp. for the disaster and disease increases. With these linked to the avg. temp, we would keep the player from being able to fix all the problems associated with warming.

Respond to global warming in disaster thread please.

**Richard Bruns** · April 2, 2000, 18:25

Vegetation Type: By "geology" I meant the shape of the land, not elevation. As I see it, there should be five land types: sunken, flat, rolling, hilly, and mountainous. Mountainous terrain limits the vegetation to scrubland or below with sparse forests, sunken terrain is described below, and everything else has normal vegetation.

Note that some places we call mountains, like the Appalachians, are considered to be hilly terrain at high elevation for the purpose of this model.

Sunken terrain is different. It would not have the wateland-plains spread like the other terrain types. It's vegetation is limited to four levels of forest cover, from No Trees to Old Growth.

High elevations would be considered arctic terrain, while some coastlines in temperate regions would be considered tropical terain.

So, each land type is a combination of geology, climate zone, and vegetation and/or forest cover. If we want, we can give a name to each combination. For example, sunken terrain in a temperate region with an old-growth forest would be called a Cypress Swamp, and flat or rolling arctic scrubland would be called Tundra.

LGJ: In many parts of the world, the natural progression is toward forests. For example, in the eastern United States, there is a lot of land that used to be farmland and is now forest. No one planted the trees there; they just grew up in the old fields.

**Lord God Jinnai** · April 2, 2000, 18:33

I 'm not saying its not natural progression, its simply takes longer to regrow than destroy.

Also we should distiquish between temperate and tropical rainforests.

**Richard Bruns** · April 7, 2000, 22:32

I just reread the map generator model. They plan on wind currents, but those seem to be fixed in place. In a map of the Earth I saw, the wind patterns looked pretty random. A planet with different continents would probably have different wind patterns. So, I suggest that the wind patterns be generated randomly at the start of the game. Those wind currents would then change the amount of water per tile.

I mentioned this on the disaster thread, but it also belongs here. Any stress to the atmosphere, like global warming, should result in those wind currents being regenerated at random. This would have a big impact on a lot of terrain, and would make climate change interesting.

I would also suggest that water currents be included. These would also be randomly generated at the start of the game and whenever the global temperature changes. The effect of water currents would be to change the temperature of some areas. Great Britian is at the same altitide as Newfoundland, but it is a lot warmer because the Gulf Stream brings warm air up from lower latitudes.

Also, I think we should use six climate zones like Toubado_Koomi proposed in the map thread. That would be more realistic than only three climates.

I am working on a model that controls ecology and farm output. I think it will give good results and only take a little processing time. I should get it done before the tech editor is finished, at which time my focus will be entering the tech tree into the editor.

**Richard Bruns** · April 15, 2000, 22:51

Sorry I've been gone so long. The school's e-mail and internet went down last monday and was gone all week, and after we were let out for break I had to go on a trip. Some of my work on this model is on the school network where I can't get to it, so it will take a few days to get everything reassembled.

**Richard Bruns** · April 29, 2000, 20:26

I’m sorry about the delay. The more I think about the model, the more complicated and challenging it seems. This is in addition to the facts that I didn’t do much over spring break and our school’s Internet access went down again soon after we got back.

The biggest problem areas, at least for me, are wetlands and aquatic ecosystems, and some of the environmental disasters. I am not totally pleased with these areas, but I am posting what I have to stimulate discussion. Maybe someone else can think of a way to improve these or other aspects of the model.

The model covers climate, vegetation, farming effectiveness, and some ecological disasters. Most of the calculations are done at the beginning of the game, so this shouldn’t take up too much processor time. I think that the initial vegetation generator should be a standard part of the game, but the routines for climate change during the game can be turned off for multiplayer games or slow computers.

My goal is not to mimic our planet. It is to generate a random Class M (earthlike) planet. This means that some things that occur on Earth might not happen exactly the same way here. I am only using general geological principles to try to create a realistic game environment that can run quickly in the background.

This ecosystem generator is designed run right after the map generator system that creates the physical shape of the land. Specifically, it is responsible for parts two and three of the posted map generator outline, which as far as I know have not been implemented yet.

I am assuming that part one of the map generator creates multiple types of terrain, something like: mountainous, hilly, rolling, and flat. I am also assuming that it tracks altitude. I haven’t seen recent documentation for all of this; I am working from the information on the clash website. If any of these assumptions are wrong, please let me know.

The first step is to generate climate zones. There are six climate zones per hemisphere, determined mainly by latitude. Each tile is assigned a base climate based on latitude:

Tropical: equator-12
Sub-Tropical:12-24
Warm Temperate: 24-40
Cool Temperate: 40-55
Sub-Arctic: 55-67
Arctic: 67-pole

As an option, there could be a bit of randomness to these numbers. It could also be possible for these to be changed in the game due to varying solar activity. This would simulate the “little ice age” that hit a few hundred years ago and disrupted, among other things, the Vikings’ colonization of Greenland.

These climate zones are modified by altitude and ocean currents. Every 100 meters above sea level is equivalent to a latitude of about 90 kilometers closer to the pole. After the climate has been adjusted for altitude, ocean current vectors are generated at random. These currents then influence the climate of nearby coastal regions. These areas are given the unadjusted climate of tiles a certain distance away in the direction that the current came from. This distance is determined by the size of the vector. So a strong current moving north in the southern hemisphere could cause lot of the nearby coastline to be changed from a warm temperate to a cool temperate climate.

The main effect of climate zones is to alter the effectiveness of farms, as warmer climates have a longer growing season. Climate will also determine what kinds of vegetation will grow in the tile, although in many cases this difference will only be cosmetic. Climate can have other uses, such as influencing the attrition of military units.

After the climate is generated, soil patches are assigned at random using a fairly broad brush. “Soil” is a term that includes every geological and chemical influence on plant growth in that area. It ranges from zero, meaning nothing at all (not even lichen) can grow, to eight, which represents exceptionally good growing conditions.

Soil is limited by climate and terrain. True arctic terrain, which is basically ice or permafrost, is limited to soils of zero to two. Sub-arctic terrain can only have soils from zero to five. Mountainous terrain limits the soil to a maximum of two and hilly terrain limits the soil to four, although terrain improvements like terracing can help out hilly terrain.

Areas beside the downstream end of large rivers are given a Soil increase of +1 to +3.

Note that some places that are called mountains, like the Appalachians, are considered to be hilly terrain at high elevation in this model.

After the soil is generated, the water rating of the terrain is assigned. “Water” is mostly rainfall, but also includes river flooding. It does not determine wetland formation or groundwater reserves; it is a measurement of how much water is naturally available to land plants. Irrigation and other terrain improvements do not change the base water rating; they provide an adjustment for farm purposes only. The water rating goes from zero to eight.

For this part of the model, the tiles are assigned water ratings in large random patches. Then, wind vectors are generated at random. If a wind current goes from the sea to the land, the coastal tiles will have a high water rating. If a wind current is blocked by high elevations, the downwind tiles will have a much lower water rating and the tiles on the windward side of the high elevation tiles will have a higher water rating. All of these ratings are then modified as follows:

All tiles in the Tropical climate zone are given a water rating of +2, all tiles in the Warm Temperate climate zone are given a water rating if –2, and all tiles in the Cool Temperate climate zone are given a water rating of +1. This is due to the large atmospheric convection cycles that would probably occur on any earthlike planet.

Water affects the soil rating due to leaching and erosion:
Water 6: Soil –1
Water 7: Soil –2
Water 8: Soil –3

Water and Soil ratings are not allowed to below zero or above the terrain limitations. If they do, they are simply assigned ratings of the minimum or maximum value allowed.

After Soil, Water, and Climate are assigned, the natural vegetation is generated. Each vegetation type can grow only in certain conditions, but most tiles will be able to support multiple types of vegetation.

In an effort to simplify things, I have come up with the “ecological province.” An ecological province is any patch of tiles that has the same climate, soil, and water. These should generally be patches of three to thirty tiles. An ecological province is assumed to be a region with almost identical environmental conditions.

Each ecological province is assigned one vegetation type out of all the vegetation types it could support. This base vegetation will not change, although the borders of the provinces could shift.

I do not have a complete list of vegetation types because that would take a good bit of time and I am fairly certain that the model will need to be revised, which would mean the list could become obsolete. But I do have samples:

Taiga
Requires: Sub-Arctic or Cool Temperate, Water 4-8, Soil 2-6
Effects: Provides low-quality softwood lumber. Reduces movement rate of units.

Temperate Grassland
Requires: Warm or Cool Temperate, Water 2-5, Soil 4-8
Effects: Soil +2. Can only be farmed if Farm Tools is at Level 30 or better (Heavy Plow)

Farming effectiveness is based primarily on the Soil and Water values of an ecological province. Each one of these is a limiting factor, so the smallest value is the basis for the crop yields. This number is then altered by climate and technology.

For this calculation, irrigation improves the Water value and fertilization improves the Soil value. In some cases, irrigation is a waste of time, and the player would be told this. However, the Water value should usually be the limiting factor, at least before the land is exhausted.

Aquatic ecosystems like wetlands, lakes, and oceans are determined by a different system. Water is irrelevant, and the ecology is determined by climate and a single Water Quality factor that goes from zero to eight. This factor has nothing to do with how suitable the water is for humans to drink or use; it describes how well the water can support life.

Wetlands are generated on land tiles, and they can have different vegetation types like other terrain. There are three types: Basin, Riverine, and Coastal.

Basin wetlands form on flat or rolling terrain where the water table rises above the land. If we use groundwater, then places with low elevation and very high groundwater reserves become these wetlands. If we don’t track groundwater, then random low elevation ecological provinces become basin wetlands.

Riverine wetlands occur alongside rivers in flat terrain. They have a chance of occurring in a low elevation ecological province that a river is passing through. Ecologically they are similar to Basin wetlands, and have the same vegetation types.

Coastal wetlands and estuaries form on flat coastal areas, often at the mouths of rivers. Because of their high salt concentrations, they have a different set of vegetation.

Wetlands can increase disease, but they decrease the chances of flooding, decrease the effects of pollution, and restore groundwater levels and purify the water (if we track this). All wetlands greatly slow the movement rate of units and are impassable to most mechanized units. Wetlands can be drained to make normal terrain, which is usually fairly good farmland. When this happens, the terrain is assigned a Soil and Water rating.

Lake and Ocean tiles also have ecology types based on Water Quality. The main effect of this will be fishing yields, but hopefully there will be undersea exploration and colonies later in the game. This will cause interactions with underwater terrain similar to the normal land interactions (movement, farm productivity, terrain improvements, etc.)

After the terrain is generated at the start of the game, it can undergo changes as time progresses. Some of these will be small and mild, but others will have a big impact on almost everyone.

The standard ecological change or ecological disaster progression is: Check, Hotlist, Countdown, Change. Checks are performed for many different reasons, and if the check is positive the area is put on the hotlist. Depending on your civ’s technology level, you can be warned about an area on the hotlist. This could allow you to take action to prevent the problem. All areas on the hotlist are monitored every turn to see if a change will really be triggered. If a change is shown to occur, the area is put on the Countdown list. You can be still warned about these events, but you can no longer prevent them. Sometimes something will happen every turn on the Countdown list, causing the change to be phased in. Other times, the change happens all at once after a certain number of turns.

The simplest and most common change is a shift in the border between two ecological provinces. This would usually result in a few tiles switching vegetation. Checks for this would be performed on one border of about fifty ecological provinces every turn. If the check is positive, the border is hotlisted. There are other conditions, discussed later, that can cause borders to become hotlisted. If the border passes two checks in a row, then it shifts after a countdown of three turns. If it fails two checks in a row, it is removed from the hotlist.

The check is:

C = Rand / ( 1+ abs(s1-s2) + abs(w1-w2) )

Where s1 and s2 are the soil values of the two provinces and w1 and w2 are the water values of the two provinces. Thus, the borders of two provinces with similar geological characteristics are much more likely to shift then the borders of two dissimilar provinces.

The check is positive if the number is above some change number defined for each terrain boundary. Some changes are more likely then others; changes that represent natural succession of vegetation would have a lower change number.

I realize that this system would change the soil and water numbers of tiles in addition to their vegetation. This is intentional; it represents natural changes in water availability and soil characteristics. The changes are likely to be gradual, so it won’t be a huge shock.

If an ecological province grows too big, it is split into two different provinces. Each province remains unchanged, but they are tracked seperately.

Human activity will influence the terrain. At low levels of habitation and use, the province simply keeps its natural state. But at higher population levels or intensive use of the tile, changes will occur.

Deforestation is the simplest human-induced change. Whenever there is a significant change in human activity on a forest province, that province is put on the hotlist. If the terrain fails two deforestation checks in a row, the forest use is assumed to be sustainable and the terrain is not checked until there is another big change in land use. If two deforestation checks in a row are passed, then the province is put on the countdown list for some number of turns. The timber yield decreases every turn, and at the end of the countdown the terrain changes. The deforestation check depends on the level of land use, the technology levels of your civ, the type of forest, and a random number representing the forest’s ability to renew itself.

After deforestation, the province is put on the hotlist for terrain change. If it is left alone and it borders other forest provinces, the forest could regrow.

Extensive farming can lower the Soil value of the terrain. Soil loss is similar to deforestation; the check works exactly the same way. If the Soil Loss check fails, then the farming is assumed to be sustainable. If it passes, the province is put on the countdown list and the soil value slowly decreases. Technology advancements can prevent this, but often at the cost of pollution.

Pollution from industry, mines, and farms can also impact terrain. The check for this change would be similar to the logging and soil loss checks. There are several types of pollution:

Acid Rain occurs downwind of large industrial centers that produce atmospheric pollution. It is most likely to happen when there is a high Water value, especially when a wind vector crosses a mountain. If the check is passed, the province is put on the countdown list and stays there until the pollution is controlled. When a province is on the countdown list, the Soil or Water Quality rating decreases at some rate that is based on the severity of the pollution. This decrease changes the maximum value, so it is not possible to fix acid rain with fertilizers. After the pollution stops, the maximum Soil or Nutrients value slowly increases to what it once was.

Liquid and solid pollution of all other types has the same effect as acid rain, but the effect is more severe and is localized to the province the pollution originated in.

Human activity can have more subtle effects on the land. Some types of land use, like extensive grazing, can cause an entire ecological province to change form. This check would combine the border change and logging checks.

There are several big environmental changes that can happen naturally. Changes in the activity of the sun can change the climate zones, which would change farm effectiveness everywhere as well as altering a lot of the natural environment. Some places would become uninhabitable, while others would be better places to live. This would prompt a lot of migrations and other upheavals. It should happen at most two or three times per game, but I think that it would be a lot of fun to deal with.

This is not the place to discuss global warming or cooling, but I should note that this model allows global warming to have huge effects. When a global temperature change of a sufficient magnitude hits, the wind and water current vectors would be changed and the climate latitudes would be shifted. A new set of random vectors would be drawn, which would change a lot of things all over the world.

I think that is everything. If I left something out or did something wrong, let me know. Any comments would be good; this is not final at all.

**Richard Bruns** · May 2, 2000, 13:29

There are a few things to add to the model proposal. Most of these additions don't really affect the core model, so I didn't include them before. But they show how the model would interact with the rest of the game, so I will give them as examples of how this model allows the Clash world to be more dynamic.

Fishing yields would be important to the economic model. As these are directly related to the Water Quality rating, anything that affects a good fishery would impact the amount of fish caught. This could result in anything from a mild annoyance to widespread starvation.

Fishing itself has an impact of the ocean. To determine if an area is being overfished, a check similar to the logging check would be done on aquatic provinces. If the province passes two Overfishing checks in a row, that province is put on the countdown list and the Water Quality rating of that area decreases at some rate. If the same rate of fishing is maintained, the decrease will accelerate until the fishery collapses. If fishing is stopped for a period of time, then the water quality can increase again as the ecosystem is restored to initial levels.

This change in Water Quality would not affect undersea farms or the base province value. It would only be a temporary adjustment for fishing purposes.

Note that in a free society, stopping fishing would not be an easy process. Also, There would be economic consequences if a large industry was stopped by the government or by the depletion of the fisheries.

Hunting is a problem. I think it should be tracked, as earlier nomadic societies could depend on it. But there isn't an easy way to track wildlife with the current system. Ideas would be appreciated.

In addition to damaging the farms and land, water and air pollution would have a chance of causing disease and unhappiness in the population.

I neglected to mention that water pollution would travel downstream and affect any wetlands provinces below the source of the pollutants. Cities downstream could also have the disease and unhappiness associated with the pollution. If a polluted river crossed the border between two civs, this could have diplomatic consequences. The same is true of acid rain and air pollution.

This model would allow warfare to create long-lasting effects on the land. They still can't farm on World War One battlefields because of the chemicals and shells in the ground. And then there is the Agent Orange option for reducing attrition due to guerilla warfare. I think it would be interesting to see if players would use a chemical like that if it were presented with a different name, or if it had a different purpose like allowing armored divisions to go through dense forests easier.

Large environmental changes could have a big impact on the entire civ. Consider the "Dust Bowl" that hit the U.S. in the 1930's, when improper land use resulted in the desertification of huge patches of farmland. The resuting unemployment, loss of productivity, and other economic problems magnified the effects of the Great Depression. Something like this could easily happen in Clash if a few provinces passed the land change check at the same time. This kind of thing would do a lot to keep the game from becoming boring, especially if the economic side of it is handled well.

**Lord God Jinnai** · May 3, 2000, 01:04

One thing: Things that would normally only be checked at the beggining of the game may have times when they need to be rechecked. These would be rare occasions though. FE: Creation of an sizable island in a water current path or a volcanoe where major wind currents are. Also if the player drastically raises or lowers a lot of land himself this might be ness. These rechecks wouldn't be for the entire globe, but only isolated areas.

Also another thing we should have based on techntonics is the increase/decrease in activity. This has happened within short periods of time and has very drastic results. We don't yet know what causes this, though it has nothing to do with pollution, greenhouse etc. It has to do with the lower layers of the earth.

**Richard Bruns** · May 4, 2000, 00:15

LGJ: You are right about the need for occasional rechecking, but I disagree with the exampled you gave. I don't think that a single mountain or island cound change global wind and water currents.

I forgot about the possibility of taking land from the sea like the Dutch did. If the player wanted to do this, there would have to be a check for the chance of success and the upkeep the land requires. If the land was generated, it would be assigned Soil and Water values. There would always be the chance of the land flooding again if the dikes were not properly maintained (or if they were bombed by a clever enemy). The dikes would have to be treatred as a terrain improvement.

Volcanoes and Earthquakes are the responsibility of the disaster model, not this one. But these would have an impact on the ecology.

The disaster that this model does affect is landslides. Defoliation or other improper use of hilly or mountainous terain would put a tile on the hotlist for landslides. If a landslide does occur, the towns and terrain improvements are all damaged or destroyed. Also, the soil rating of the tile would decrease by one or two.

The ecology model would have to be one of the last models that is actually implemented because it requires inputs from almost all of the other models and the impacts it has cannot be quantified until the other models are complete. I am discussing the model now so we have a general idea of how it would fit in and how it relates with everything else, but the actual number crunching cannot be done until after everything else has been finished.

**Richard Bruns** · May 5, 2000, 09:36

I recently finished studying for a test on ecosystems, which reminded me of some other effects of environmental change.

Deforestation will often result in a lot of soil loss due to erosion. Deforestation would result in soil losses of zero or one on flat terrain, zero to two on rolling terrain, and one to two on hilly terrain. This soil loss would be a permanent change for the province. Also, the province would be assigned a lower change number for border changes, so the surrounding provinces would be more likely to move in to replace the former forest province.

Widespread construction in a province has a chance of reducing that province's soil value by the same amounts as deforestation. Construction in mountainous terrain would reduce the soil value by one to three.

This and other soil loss will affect water quality. Whenever soil loss occurs for any reason other than farming and border changes, any bodies of water in or adjacent to the province will have their Water Quality temporarily reduced by that same amount. So if deforestation reduced the soil of a province by one, and then a landslide reduced the soil value by two, the Water Quality rating of a river running through that province would be temporarily reduced by three.

By the way, I'm starting to like this system more. It passes the flexibility test; it is able to easily include things that I hadn't considered when I first made the model.
[This message has been edited by Richard Bruns (edited May 05, 2000).]

**Lord God Jinnai** · May 6, 2000, 00:13

On Soil Ersosion:

When you say "permanent" do you mean for the rest of the game? If so I will have to say you are wrong there. Given enough time and left alone (or you can aid this processs with correct tech) a place can usually restore itself, some things more easily restored than others.

With that in mind it also brings to surface another fact: All this soil must go somehwere, and where does it go? Usually most erosion is by water and is carried by rivers and streams which eventually end it deltas. These deltas will continue to have rich soil and the land area will grow over time. The best example is the Fertile Cresent which during the times the first civilizations were into being, the delta was so far back the Tigris and Euphates rivers never conncected and cam as close as 20 miles. The land area has increased enough to add atleast in the clash mapping scale atleast (prob more, thouhg not too many) 1 extra tile of habitable land area.

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Vegetation, Climate, Ecology, and Pollution

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