New Unit Storage/Fuel/Ammo Ability

[yoshi]

I've found that in Civ3's core game, the fact that units have no limitations on range causes function at an accelerated rate. For instance, there is nothing stopping the French on an Earth map from building a Warrior unit and sending it accross the the world to make contact with the Chinese. Aside from being almost historically blasphamous, it means that there is just as much diplomacy between distant civs as there is between neighbours.
The other problem is that there is nothing stopping a civ from sending its civs to distant lands to make war.
The solution is to give units 'Storage.' This would mean that a unit could only spend x number of turns outside friendly territory (i.e. within ally's or own borders) --this could also just be limited to cities. Once a unit gets to its half-way point, you get a warning of some kind. If a unit stays out longer than that, it gets an ADM penalty and eventually disbands (for instance). Units in Fortresses outside of friendly would consume Storage 50% slower --unless that fort/base was connected to friendly territory by an unblocked Road/Railroad, in which case the unit would never run out. This would also keep civs from colonizing too far away from thier own territory --something that the AI excels at, as we all know.

An additional limitation should be placed on powered units, since in this case it is not enough to simply be in friendly territory.
As I noted in the 'Storage Depot' thread, giving units a refueling ability would make such units dependent on fuel-based Strategic Resources. Like a Storage limit, the need to refuel would ensure that naval units must occasionally return to port instead of eternally circumnavigating the globe without limitation. A unit's fuel would be consumed based on the number of times a unit moves before runnign dry, not turns. This would add a whole new level of strategy to the game, which as far as I am concerned, would a particularly good addition to Conquests considering how combat strategy-based it is meant to be.

Although less innovative than the above to requests, the idea of placing ammunition limits on units is still relevant: having ranged units that never have to go back to a city to reload makes them essentially into non-ranged units with a ranged animation. Not doing so would give ranged units too much of an advantage when defending friendly terriory. Re-arming would be done in cities and bases connected to a city by road. This addition would be particularly useful for creating more in-depth combat-based scenarios.

For those players who preferred not having such limitations, an in-game preference could deactivate them (or activate them) --thus the game could play either way.

 

[yoshi]

I don't believe it. Two days and not a single reply! C'mon people, any reply will do. I hope this is because of the power outage...

 

[Vietcong]

yap. units shold need suplys or a suoply line. say stary a sea convoy for this city and end in this squar

 

[Aussie_Lurker]

I 100% agree, and have said so in MANY different threads!! Basically, a unit should have an "Operational Range", with each era having a higher average OR than the one before! Also, mech units would have a lower OR than a mounted unit which, in turn, would be lower than a foot unit!! Workers, spec-ops and settler units would have the BEST OR's in ANY era!!
Anyway, OR would refer to the number of tiles OUTSIDE of your border that the unit can go! Any further, and it begins to suffer damage-each turn! The only way to 'extend' your OR is to build a fort, and connect it to your territory via a road! If the fort is captured or the road/rail connection is severed, then your unit is suddenly 'out of range' again!! This is just the 'bare bones' of my idea, but I don't see why it couldn't be implemented!

Yours,
Aussie_Lurker.

 

[yoshi]

That's amazing. Judging by your response you didn't really read my intro post but that's okay, it was too long anyway. What's amazing is that if you read it you'll notice that almost everything you mentioned is very similar to the 'Supply' part of my own post! And I've read other posts on the subject that also include some of the stuff mentioned here. That means that we're all thinking along the same lines. In other words, I hope someone from Firaxis/Atari sees this thread, because this is obviously an addition worth considering.

units should need suplys or a suoply line

That's were the Fortresses/Air Bases connected by Roads come into it. By building these improvments along your route and connecting them all to a city or cities, you extend your units' range because they can resupply on the spot. The defending civ can then engage in scortched earth warfare (destroy irrigation; i.e. cities can only resupply units if they have enough available --that would require a little programming thought) and pillage the Roads connecting your Forts, thus starving your units. If you're familiar with Napoleon Bonapart's disasterous campagn in Russia, you will see what I mean.
I was also thinking about extending units' range using Armies. One way of doing this would be to give the 'Army' unit a flag like, "100% Supply Bonus" which would give all the units loaded into an Army a greater range when outside of friendly territory (borders/ally's borders).

If unit Fuel were included, then cities connected to your bases would require access to a 'fuel' resource (Oil) for you runits to refuel at those Bases. Keep in mind 'fueled' units would have to both re-fuel AND resupply.

 

[tctatheel7]

this is one of those rare, very good ideas, that are historicly accurate, make sense, and would add an new sense of strategy to the game i like it

 

[Commander Bello]

Although I admit that implementation of supply chains would add depth to the game, I see a lot of problems occur...
First, the key factor of supply is that it is brought to the unit. In former times, this typically has been done by the sutlers to accompany an army. In modern times, armies have their supply units, which will provide the combat units with ammo, fuel, food....
As far as naval warfare is concerned, this is done by tankers. In the sailing age, this was of less a problem, since the only supply needed was the ammo (otherwise Cook, Magelhaes and others wouldn't have been capable of sailing across the globe)
Second, if we assume that this supply is brought in automatically ('invisible' little trucks running around and 'supplying' the combat troops) then there is the problem of how to determine, when a supply line might be interrupted.
Third, the 'micro-management' of supply seems to become more important with modern (that is, fuel-based) units. Foot soldiers and mounted (riding - on whatever animal) troops can get their supply from marauding the surroundings. In fact, that was the way they got their supply during the '30-years-war' (don't know about the right English name for it - the war from 1618 to 1648 between Catholics and Protestants in the Holy Roman Empire of German Nation)
Fourth, how then to maintain supply lines if you try to perform landing operations on the next continent?

 

[yoshi]

You may have misread something so I'll summerize:

The effect of supply lines is reproduced by units re-supplying/re-fueling/reloading in Fortresses/Air Bases that are connected to a City by Road. In order to re-fuel, the connected city must in turn be connected with the appropriate fuel resource (Strategic Resource; e.g. Oil, Coal, Uranium).

This reproduces the effect of supply lines.

Placing an enemy unit on the connecting Road or Pillaging it cuts the 'Supply/Fuel' to that Fortress/Air Base (units do not disband while in a Fortress/Airbase --because you can re-connect it).
Blocking a 'choke point' cuts the connection to a resource in a coastal city (with a Harbor).
In other words, it works exactly the same way as Roads do in Civ3 now (where resources are concerned).

An additional proposed effect would b to give Armies a special 'Supply Bonus' ability that would extend the number of turns it can remain outside freindly territory. This reproduces the effect of supply lines that are linked directly to the Army.

As for Naval units, the tanker effect (refueling ships at sea) isn't covered in this because having 'freight' units running all over the place would clutter up the map, slow down the game and require a great deal of new program information --divergess too far from Civ3 rules. Ships can't be loaded into an Army either, so the Bonus supply doesn't apply here.
The idea with ships is similar: in order to be 'global,' owner/ally must have strategically placed coastal cities along the ship's route. Before mechanized propulsion, the only reason to have coastal cities is to be able to resupply --ships carry a lot of supplies so naval units would not be as limited in terms of 'running out of food.'

I was also contemplating being able to 'buy' supplies from another non-allied civ. you would move your unit into their territory and attempt to move into one of their cities. you would get a pop-up with the options, "Buy Supplies for cost of x gold" and "Attack City." The x is determined automatically based on your standing with that civ (Allied units pay nothing). This would be very helpful if your ships are exploring beyond the point-of-no-return.

'Supply' applies to all unit in all Ages except to certain 'special' units like Guerillas (they live off the land). This is actually just as, if not more, important in the early Ages as it is in the Modern Age because it keeps units localized; i.e. limits their range.
'Fuel' is secondary to supply as it is not as essential to general gameplay but it is still of high strategic releveance in the Modern Age, so I certainly wouldn't dismiss it.
'Ammo' is a luxury, what can I say. But it does prevent non-mechanized Ranged units from just attacking/defending ad infinitum. it would have more use in highly detailed modern scenarios. In order to make it compatible with the core game, I was thinking of adding a rule feature that only reduces Ranged unit A/D by 50% when they run out --so that the units don't become completely helpless, which is not realistic either (this feature would not apply Bombardment; i.e. when you run out, you run out).

Where inter-continental warfare is concerned, supply lines are maintained by having a coastal city with a Harbor on each continent. That is, it would be exaclty the same as it is now where you need a city with a Harbor to allow cities on the 'new' continent to build units that require resources only available on the 'old' continent.


I hope that clears things up a bit.

(It's nice to see someone read my post in 'Longshot Combat!')

 

[yoshi]

The fact that 'naval supply routes' (cities connected by Harbor) cannot be blocked except by placing a unit(s) at a 'choke point' (inlet) is something that I have never liked about Civ3. In Civ2 you could destroy transport ships carrying Caravans/Freight thus preventing trade. In Civ3, you can't block the trade in 'mid-route.'

The only way I can see to get past that is to have an 'Intercept Air Freight' feature that activates when you 'teleport' a unit between airports over enemy air units. So in this case, if enemy ships are somewhere in the area of the 'route,' the trade may be intercepted --an additional bonus would be to recieve gold if intercpet is successful (piracy).

 

[yoshi]

In the sailing age, this was of less a problem, since the only supply needed was the ammo (otherwise Cook, Magelhaes and others wouldn't have been capable of sailing across the globe)

I contemplated this. As I said, ships would have a high Supply value ut it still wouldn't allow them to sail around the world. It isn't worth rethinking my entire supply concept just for this exception so I think we should assume that ships on long voyages like that would have to get new supplies (that includes repairs and other stuff) from the other civs along the route.

Oh, I forgot to mention that units could not 'buy' supplies from civs that are at War with the owner --this should need no explanation.

I forgot to address the issue of micromanagement. Resupplying would be simple enough: units just have to enter into city (or a connected fort/airbase) to resupply. The same goes for Fuel and Ammo. To resupply at an allied city, just attempt to move into the allied city and the unit will be resupplied at no cost. The same goes for non-allies (who are not at war with you) but there is a cost involved. Considering this, micromanagement is very low (or at least not much more than it is already).

I was thinking that Supply should consume food in your city (i.e. units consume x food from city's Food Box each time they resupply).
A more generalized 'cost' solution would be to have a cost in gold for Supply/Fuel/Ammo that would be determined in the 'General' window of the Editor --the cost could also be propotional to the unit's cost (e.g. Battleship costs more to resupply than Infantry).

Sorry for the rant.

 

[Commander Bello]

100 ways how to be mean to Yoshi

Ok, here are my concerns.....

First, no civ will allow you to enter their territory with your military units unless you have a ROP. Instead, you will spoil their opinion towards your nation by crossing their borders, even more when getting close to their cities. Otherwise, this would be a perfect for attacking, wouldn't it? 'Oh, our 37 swordsmen are just in to get some coffee, ya know?'
Second, how will you explore the world at the start of the game, unless you offer scouts to all nations?
Third, you would easily starve your border towns to death, if supply would consume food as well.
Fourth, it wouldn't be handeable to fight your way towards a heavily defended enemy town when you would have to withdraw your troops every x turns to supply them somewhere in your own territory. (Don't know in the moment, whether you are allowed to built fortresses in enemy territory - but this might take some turns as well, thus creating the need to have a lot of your workers somewhere at the front, by that causing the need to have a second army just to protect them against enemy counter attacks)
Fifth, if you are allowing air interception for air supply, then we are talking about interception in total - by that making air transport over enemy territory almost impossible.

Ok.. the other 95 ways are to to follow

 

[Commander Bello]

Originally posted by yoshi
The fact that 'naval supply routes' (cities connected by Harbor) cannot be blocked except by placing a unit(s) at a 'choke point' (inlet) is something that I have never liked about Civ3. In Civ2 you could destroy transport ships carrying Caravans/Freight thus preventing trade. In Civ3, you can't block the trade in 'mid-route.'

The only way I can see to get past that is to have an 'Intercept Air Freight' feature that activates when you 'teleport' a unit between airports over enemy air units. So in this case, if enemy ships are somewhere in the area of the 'route,' the trade may be intercepted --an additional bonus would be to recieve gold if intercpet is successful (piracy).

All games face severe problems when trying to simulate blockades. I guess, this could only be solved by the use of ZOC-concepts. There could be a new option for warships, called 'blockade' by which a ZOC (which on open sea makes not much sense) is created. Thus, three or four ships could be enough to block harbors efficiently and not being endangered by the coastal defences.
But, as soon as a ship (with A/D values - probably it would have to be a surface ship) manages to leave or enter the harbor, this ZOC-option could be disengaged for all ships within a certain range from that harbor for up to three turns.
Treaties being dependant from the trade which took place in this harbor could be suspended as long as the blockade works... So, you would no longer deliver your luxuries, but they would be in a certain 'customer-related' stock. Of course, on the other hand, you wouldn't get the 50 gpt either. As long, as the treaty is in place you wouldn't be allowed to use these luxuries then for your own purposes.
For air interception, it would be different. All planes should have an operational range so that they just can't fly to the other end of the world [edit: Nevertheless, their use of this operational range should consume nil time. By that, airplanes still could be rebased in the one and same turn from here to there - as long, as the distribution of friendly airbases on the map allows for that].
Combat planes as fighters and bombers would try to use the direct way. If they enter the interception area of an airbase they encounter air interception (by the way, this means that [edit: hostile] interception zones which overlap [edit: with your air interception zones], would cause air combat between the fighters - something, which is missing in CIV3 anyway).
The virtual air transport would have to [edit: avoid] those interception areas. If the operational range than doesn't allow to reach the target airbase - voila, no air transport.
Additionally, there could be a map feature to display the routes of the air transports, if needed. So, you could see where the 'intercepting' enemy air base is located and try to get rid of it.

 

[yoshi]

100 ways how to be mean to Yoshi

Not at all. I appreciate the input.
Although it would be nice if players other than just the usual few were to post on my threads. The more (objective) issues that are raised, the more I am able to deal with the various glitches in the concpets brought up in my threads.

First, no civ will allow you to enter their territory with your military units unless you have a ROP.

You're referring to the idea of being able to resupply at the cities of non-allied civ that you are not at war with right? I didn't really address that did I? The only way I can see around that is to add a temporary ROP treaty into Civ3 diplomacy (i.e. only gives 2-3 turns of ROP --just enough to resupply and get out). I was thinking along the lines of speeding up this feature so that you just get a pop-up or something.

Second, how will you explore the world at the start of the game, unless you offer scouts to all nations?

Scouts would also have a Supply limitation (to prevent them exploring the whole land map --which is part of the point behind Supply), it's just that it would be significantely higher than military units so as not to limit its range too much.
BTW, I personally mod my games to give all civs at least 1 Scout unit so as to balance things out a bit --due to the lack of range limits on units, civs usually have contact with every other civ on the continent within the first part of the early game.

Third, you would easily starve your border towns to death, if supply would consume food as well.

Good point. I was only toying with the idea --not essential.

Fourth, it wouldn't be handeable to fight your way towards a heavily defended enemy town when you would have to withdraw your troops every x turns to supply them somewhere in your own territory. (Don't know in the moment, whether you are allowed to built fortresses in enemy territory - but this might take some turns as well, thus creating the need to have a lot of your workers somewhere at the front, by that causing the need to have a second army just to protect them against enemy counter attacks)

I'm not sure about the Fortress thing either, I've never found use for it (Supply would change that, which is good) --if you are prevented from doing so, then that would only require a simple rule change, the hard part is getting the AI to build fortresses in the appropriate locations.
As for the need for many Workers just to build a Fortress, just decrease the time required to build them (they take way too long to build anyway).

Fifth, if you are allowing air interception for air supply, then we are talking about interception in total - by that making air transport over enemy territory almost impossible.

I think you misunderstood the Harbor thing. What I was saying is that the more enemy ships along the 'route' increase the chances that the trade/resource/supply will be intercepted --it was only an idea to give piracy a little more 'umph.'
But you do bring up another point: can you use Airports the same way you use Harbors (i.e. creating invisible 'Road' between two or more Airports)? I'm pretty sure that feature isn't in Civ3 and understandably so: if you could just use Airports, then connecting cities with Roads and Harbors would be pointless --besides, heavy goods are rarely transported by aircraft anyway.

Ok.. the other 95 ways are to to follow

Okay, I'm starting to have second thoughs about what I said at the beginning of my reply...just kidding.

Thus, three or four ships could be enough to block harbors efficiently and not being endangered by the coastal defences.

That's the idea behind the 'intercept' thing I suggested.

But, as soon as a ship (with A/D values - probably it would have to be a surface ship) manages to leave or enter the harbor, this ZOC-option could be disengaged for all ships within a certain range from that harbor for up to three turns.

I don't get this part. Is this to simulate 'blockade running'?

Treaties being dependant from the trade which took place in this harbor could be suspended as long as the blockade works...

Yep, that would definitely be a required feature if blockades are constantely taking place.

All planes should have an operational range so that they just can't fly to the other end of the world

I think Conquests will address this problem.

Additionally, there could be a map feature to display the routes of the air transports, if needed. So, you could see where the 'intercepting' enemy air base is located and try to get rid of it.

This would be the simplest solution to Ocean-going routes. Just use a similar system to 'Call to Power' (only unlike CTP, on land the line would follow Roads instead of just going in a straight line).

-----------------------------------------------------
This is a thread that I'm quite interested in so I will probably answer most posts (that are related to the thread), so keep posting stuff!

 

[Commander Bello]

@ Yoshi:

I don't get this part. Is this to simulate 'blockade running'?

Now I don't get it But that will be caused by some deficiencies of my person, as far as English is concerned (about the other deficiencies, I don't discuss them here )
What I meant was, if a warship (for that the A/D values) manages to get in or out of that blocked harbor, then this simulates that the blockade has been broken (at least, we call it this way in German - missing the correct English term...)

I'm pretty sure that feature isn't in Civ3 and understandably so: if you could just use Airports, then connecting cities with Roads and Harbors would be pointless

Well, it's already late over here and maybe, I'm missing the point again. But, yes, you may use airports as an substitute for harbors... The funny thing is, that you can send only one unit per turn from a certain airport / airbase, but the receiving airport / airbase has no such limitation. This is nice for intercontinental warfare in modern times, since all you have to do is to have a worker with your landing troops to create an airfield. Then you put some good defenders on it and then you may fly in your tanks.... If you do so at two different sites, some 20 tiles distance in between, then the game for AI is over....

As for the need for many Workers just to build a Fortress, just decrease the time required to build them (they take way too long to build anyway).

Oouuch!!!
Sometimes, one just misses the easiest solution... unbelievable, but true... That will be the solution to both, the fortress issue as well as the airbase thing, which I mentioned above...
Fortresses are to become cheaper, airbases have to become much more expensive..

 

[yoshi]

What I meant was, if a warship (for that the A/D values) manages to get in or out of that blocked harbor, then this simulates that the blockade has been broken (at least, we call it this way in German - missing the correct English term...)

Yes, that would be blockade running. This would be expolited by human player who would just keep moving their ships in and out of the 'blocked' port. But it does address the other glitch of having only a few ships 'blockading' thus preventing trade ad eternum --the chances of blockading would be lower if there were only a few enemy ships in the area though.

But, yes, you may use airports as an substitute for harbors...

I meant that you can use airports to transport units but not to create trade routes.
(Personally, I never liked the airport ability since interception is completely randomized. I tried taking away the 'teleport ability' from the Airport improvment in a mod and replaced the 'airlift' ability with an actual air unit that can be loaded with units --unlike the Helicopter, it cannot Air Drop and can carry all types of land units. Now if you fly through enemy territory where Fighter on the 'Air Superiority Mission' are present, the Air Transport unit will probably be shot down.)

airbases have to become much more expensive..

It would also be nice if your Workers actully BUILT the airbases instead of losing the Worker to create the Airbase --I can only imagine that designers added this so as to prevent players from building Airbases all over the place (your idea of just increasing the build time is better and would save a Worker). What's really stupid is the fact that you lose a Worker just to build an Outpost!


For your viewing pleasure, I have added this mock-up section that would be placed into the Editor's 'Units' window (just to give you a clearer idea of what this could look like):

 

[yoshi]

BTW:

'Resupply cost,' 'Refuel Cost' and 'Reload Cost' are all paid in gold (Resupply would not cost Food as was mentioned before).


I added the 'Life' field just for fun --I've always wanted the option of having units die out after a time (hey, when in Rome).

 

[Commander Bello]

About the "dying out" I would prefer that those units first would be degraded - from elite down to veteran down to standard and so on. By this 'marauding' could be simulated with the fact of losing more and more control over your troops going hand in hand.
It should take some turns before a unit would be down-graded.
On the other hand a unit being subject to this down-grading process should no longer cost gpt, this way simulating the lost contact to the mother country.

 

[yoshi]

As I said, I added the 'Life' field just for fun. I guess if you added degrading HPs it would serve as a sort of warning that the unit is on it's last legs --so you don't make the mistake of sending it out to battle.


Either way, I was thinking about this Supply business and I don't think there is a chance in hell that it will ever even be considered by Civ3's designers. I think most players don't want this anyway --it would add complexity to a game based on absolute simplicity.
I personally think that the other reason is that many players (probably the majority of them) don't like change unless it's very slight and specifically sanctioned by the developer. And furthermore, 'limitations' like supply would make the game more challenging (difficult) thus tried-and-true strategies like building a whole bunch of units (regardless of population size) and sending them across the globe to conquer an unsuspecting AI civ, would no longer work --that would really be too bad wouldn't it... Some thought would have to be put into conquering and that's a no-no. I'm not bitter at the apparent fanatical conservatism of many players but I am embarrased at their small mindedness --aren't strategy gamers supposed to be a little more enlightened than most? Civ3 clearly puts a swift end to that theory.

I have to admit that the only reason why I even bother with Civ3 is that it offers things that should have been in Civ2 but weren't --probably due to the same reason Civ3 is...what it is. Just to be fair, I won't put the blame on most players because developers are really to blame for setting low standards that players have just gotten used to. The fact that when you request something that would change the game more than just a tiny bit and you get the response "maybe in Civ4" is an example of this. Let me say now that most of the cool stuff requested on this forum won't be in Civ4 or Civ5 or Civ6 either! Why? Because there are just too many small-minded people in the industry who are only willing to take in feedback from equally small-minded players. But that's just my opinion and I hope I'm wrong.

(The fact that the AI can't handle any of the stuff already in the game, let alone this new proposed stuff is probably due to similar reasons as those stated above.)


You'll have to forgive me for the occasional rant but sometimes you have to wonder if designers don't make these games flawed just as an excuse to say: "We plan to fix all that in the NEXT expansion" (which of course you have to buy in order to get what you rightly expected to get in the previous release).

BTW, just to those of you who say that this is just a game: personally, I don't want 'just a game,' I want a challenge that won't take me several lifetimes to complete (i.e. more strategy vs. long turns). If I want 'just a game' then I'll go play Mario or something where the challenge is nothing more than jumping over Koopas and not falling off sewerpipe teleporters.

As far as I'm concerned, the more strategy (i.e. more factors, like Supply for instance), the better.

 

[yoshi]

On a lighter note:

I tried experimenting with adding supply into a Civ2 scenario. I basically gave a 'General' unit the 'Carrier' flag and gave all other military units the 'air' domain with a limited range. Thus, the only way of getting these units to the enemy was to move them along in a stack along with the General.
Interestingly, the AI in Civ2 knows how to use 'land' Carriers' because it essentially treates them as cities (it doesn't know how to use Airbases or sea-Carriers, which is so bad it's embarrasing).
So, the AI would actually move the military units (with 'Air Superiority' --Fighter-- flag) along with the General. In order to get the General to go towards the enemy but not attack, I just gave the unit the 'Submarine' flag and gave it high attack value. Unfortunately, when an enemy unit was revealed, the units would leave the General and make a vain attempt at attacking the enemy...and would consequntally run out of fuel. This is what in technical language is called an AI STUPIDITY! (See? It's almost like designers WANT the AI to screw up!)
Anyway, aside from the obvious exploit of Infantry entering coastal Ocean squares (I gave the units 1 or MPs withCoastal flag so that they can't go beyond that --AI ignores the 'sinks' effect...argh), this worked fairly well for the human player.

Civ3 doesn't even offer this option. I couldn't think of any way of limiting units in Civ3. Nothing. Zip.
Some sort of supply limitation would be nice for scenarios, no matter how primitive the system --even if the AI doesn't have a clue how to use it...then, what else is new.

 

[snowmelk]

Well, basically I like the idea of supply limitation.
A simple system that I can imagine would work is a range stat for units. Unit movement would be like it is now, but restricted to your own territory plus number of squares according to the range stat. No active resupplying, you just activate a unit and tiles out of reach are shadowed (or marked somehow else). You move your unit inside its range and that's it.
To extend your unit reach you can build road connected supply stations, which in terms of programming would just give that tile your nationality. Since your units can move inside your territory and to an extend of their range stat outside it, their range will now be extended. Very simple to play, pretty simple to program (I guess, at least...) and I can imagine that even the AI could understand that.
If your territory border changes (because the road connection is lost or the supply station or a city is lost, units suddenly out of range are grounded until they get back in range (by reconnecting the road or building new supply stations or cities).

Range values:
"Normal" land units:
Foot units shold have higher range stats than mechanised units, scout or some special units should have the highest.
Keep it simple, maybe three or four different stats in total, otherwise you confuse too much players and surely the AI...
Sea units and explorers:
Range stats for ships and explorers should be very high, much higher than "normal" unit stats. These units should be able to move almost unrestricted (since you can't build supply stations on the oceans, supply ships are too complicated and even sailing ships can move around the globe), exept maybe the earlyest ships.

I know that this is not half as detailed as the proposals in the earlier posts, but is has IMO one advantage: It's simple enough to make it's way in the game.
It's shurely not the system to open the way to brilliant and tricky logistical tactics, but it will add the point of supply to Civilization. The game changes are compareably simple. Still it will give you a whole bunch of new strategical possibilities. Destroying enemy supply lines to ground his troops and secure your own. Choose between mechanised troops with more firepower and foot troops with higher range. Where to build supply stations (maybe you can't defend them all, or maybe they have maintenance costs) and so on...

Think about it!