Visibility

[SlowThinker]

I collected some stuff about visibility.
Some things need more testing, so you can help...

[SlowThinker]

CITIES
visibility of a city:
2 space - units with attack>0
1 space - units with attack=0 (a sidenote: 0-attack units don't block square production)

Units in opponent's cities are not visible, you only see a flag if there is a garison in the city. But they may be visible by your cities (if they are within sight of your city; the rule that units attack=0 are invisible in an outside city's circle is still valid): so in relation to a visibility of a city, squares of opponent's cities are treated like normal squares.

"SEE 2" UNITS
units with a 2-space visibility:
ground units still see only 1 square to the ocean
naval units still see only 1 square to the ground
air units see 2 squares everywhere


STACKS
stacked units have a shadow (this is a way how to distinguish stacked and non-stacked units)
there is a trick how to find out number of units in a stack: [http://apolyton.net/forums/showthrea...hreadid=159432]Knowing the size of stacks[/url]
AI 'sees' all units of the stacks (for example it doesn't attack if there is too strong unit in the stack)

order of units in status window: (I mean after you right-click a square and no unit is flashing)
units with attack > 0 first (including air and sea units); new incoming units and present units that have attacked (defense against an attack doesn't count; a unit that defends is seen only a short period during the combat) are ranged on top,
then units with attack = 0 (in a reverse order: new incoming units are ranged on bottom; no analogy with attacking: a dip that have bribed doesn't change his position)

which unit from a stack is topped on the map? It is the first unit of the status window, except air units have priority

warning: if you test in cheat mode then take into consideration that a unit created by a cheat mode is always topped

a ship with a cargo:
if ship has attack>0 then only ship is shown
if ship has attack=0 then ship is shown on the map but the "top" unit of the cargo is shown in the status window (also if it is a 0-attack unit)
to TEST!! what is the "top" unit of a cargo?


"VISIBLE" STATUS
A revealed unit (not only the "top" unit of the stack but all units that were in the stack in the moment when the square was visible) gets a "visible" status. The "visible" status is lost once the unit moves (it is still visible if it attacks without a move).
Among "visible" units of a stack you see the current "top" unit (although it was underneath of the stack in the moment when the square was revealed). Non-visible units in the stack are ignored.
If the "top" unit of a stack is not "visible" then the square appears to be empty.
(to TEST: if there is only one "visible" unit in the stack and it is the "top" unit - is the shadow of the stack visible?) I suppose non-visible units are ignored completely.

If the "top" unit is a submarine then the square appears to be empty (for units without a "see submarines" flag)
(to TEST: I am not sure if it always worked...)

So there is no "visibility" of squares but "visibility" of units.

exchanging maps: all units get the "visible" status (including units in cities). Of course the status is lost after a unit moves.
to TEST - is damage of "visible" units actualized or not? In cities, ouside of cities? Status (fortify, mine, sleep) - is it actualized?
to TEST - Seeds PBEM 2770 133,71 - top of the stack on map an on the status window are different (just a note for me, I can't open the map since the PBEM is still running)



SLEEPING UNITS
when is a sleeping unit (any domain) awakened?
It must see a square where a foreign unit is activated or where a unit is getting his feet to
sleeping units on boats are never awakened by a foreign movement


SUBMARINES
submarine is not seen, only if a foreign unit is trying to step directly on a submarine, or if it creates a ZOC (ground subs only);
'see submarine'+'see2' still sees subs to distance 1
submarine creates a shadow if stacked

(ground) submarine creates ZOCs;
submarine doesn't awake a sleeping ground 'see sub' unit (on both land and sea square); it does awake a naval 'see sub' unit on a sea square (not in a city);

submarine doesn't see ground units on ground; it does see naval units on ground and both naval and ground units on sea; it does see cities.

submarines cannot attack land units


TERRAIN CHANGES
if a settler changes terrain all civs that have that square revealed see the change (no need to re-visit the square )
but new terrain improvements (roads, irrigation ...) + pillaged terrain improvements are not seen unless you visit that square; even a city doesn't see it, but you can notice an increased production in a city window
to TEST: a map exchange with a civ that visited the square in new status helps? Does it works properly (map exchanges managed by Yaroslav's CivDip don't). Will Civ2 find out correctly who's map is more fresh?


************************************************
MP VISIBILITY

City road bug: a roads under a city may be seen although the city is not seen (such a road is shown on a map but not mentioned in a status window):
works only in MP mode (?) (it works with Seeds PBEM I am playing; this PBEM is run in a .net mode):

(old hypothesis, this is probably not true: )
city road bug: if you see a road on your map (it needn't exist) and a city is built besides then you see a road on that square
(a new hypothesis: )
if you stepped on the square (or besides it?) and a city is built there later then you see a road on that square

HOT SEAT VISIBILITY
City road bug doesn't work
a visible road doesn't disappear after it was pillaged; but it dissapears if a city is destroyed/disbanded
a road (with all its continuation - I mean roads connected to the first revealed road) is visible after checking ZOCs
to TEST: more stuff


************************************************
ZOCs
a 'check-ZOCs' trick: try moves that are clearly impossible because of ZOCs. You may reveal new foreign units.

ZOCs are caused by units that are positioned on ground (ships included)
also 'ignore ZOC' units create their own ZOC
if one of squares [start of movement, end of movement] is ocean or a city (own or foreign) then ZOCs are ignored
if start of movement is ocean and end of movement is ground then ZOCs are ignored
if start of movement is ground and end of movement is ocean then ZOCs are ignored (ie. 'check-ZOCs' doesn't work in case of units hidden on ground; but units hidden on ocean squares will be revealed this way)
Edit: all this paragraph seems to be a bit chaotic and maybe is not completely true. It should be tested again and rewritten. Anyway it is true that a ground unit can reveal naval units if it checks ZOCs by trying to step into ocean

ZOCs of multiple foreign civs are combined

[Elephant]

Terrain changes in scenarios with revealed maps give away too much info. Is there a way to reset the "most recently visited" flag so that more recent irrigation or city creation is not immediately visible?

[JCP]

Re: Visibility

Originally posted by SlowThinker
I collected some stuff about visibility....

Interesting !
I'll try some hypothesis...

[SlowThinker]

Originally posted by Elephant
Is there a way to reset the "most recently visited" flag so that more recent irrigation or city creation is not immediately visible?

What is this flag?

[Elephant]

Each land tile of the map seems to have a property that someone titled "most recently visited flag" (I read that in several places a few years ago). Whichever civ had a combat unit move through the tile last gets it's number recorded. If you are playing with "show enemy moves" set on, and you were the "most recently visited" (or you got a glimpse of other's maps from a map trade) you will see other civs units move into that tile - but that then resets the flag and you see nothing more. Non-combat units like dips, caravans and settlers don't seem to reset the flag. The property I was referring to, though, was once you have made the map visible to all, whenever another civ changed the terrain around their own homeland it showed up on everyone else's map. I presumed that the occasional lack of being visible was because an AI combat unit reset the flag.

[Peaster]

ST - Thanks for posting this. Maybe you could also mention Historical Atze's trick for knowing the size of a stack. Related to that, you can sometimes see the top unit inside an opponent's city by right-clicking on the city. But I don't know the rule for when this is possible. For me, it seems to work more often against AI's than humans. (?)

Please forgive me if that was already explained in your post. I am a bit confused by the first section, CITIES. Are you explaining when you can see an opponent's city ? In one PBEM, my opponent (you) built a city next to one of my fortified units, and I never saw the city until I activated the unit. Also, it seems that once you see a city, you will usually see when the flag is up. You will sometimes know when the city grows [MP games] but not always [SP games?].

But maybe you are referring to what you can see near one of YOUR cities? I think you sometimes get different info about opponents' units from the world map and from the city map, but I'm not sure of the rule on this either.

My main question is - when can you see an opponent's unit which is not near one of yours ? For example, we have all seen barbarians approaching when they were still 4 or 5 squares away. But usually enemy units are not visible until 1-2 squares away.

EDIT: Maybe Elephant just answered my main question. I had suspected this, but for some reason that I've now forgotten, didn't quite believe it. Has anyone tested this carefully?

[SlowThinker]

Peaster said:
>My main question is - when can you see an opponent's unit which is not near one of yours ? For example, we have all seen barbarians approaching when they were still 4 or 5 squares away. But usually enemy units are not visible until 1-2 squares away.

Once a foreign unit gets into a vision-radius of any your unit or city, it gets visible and it remains visible until until it moves. At this moment the map is centered on the unit and it disappears. If you are playing with "show enemy moves" set on then you see also the direction it leaves.
Barbarians are an exception - they are visible anywhere on revealed map. At least I believed it until now, your question puzzled me a bit.

Elephant said:
>Whichever civ had a combat unit move through the tile last gets it's number recorded. If you are playing with "show enemy moves" set on, and you were the "most recently visited" (or you got a glimpse of other's maps from a map trade) you will see other civs units move into that tile

I believe this is a myth. I remember an old thread (maybe in the MP-forum, but I wasn't able to find now, it may be in archives already): some seasoned MP-player (rah?) claimed this myth too, so I ran some tests and it never occured.
It looks the only effect of the "most recently visited flag" is it counts terrain for the "land size" in Demographics window.

Elephant said:
>The property I was referring to, though, was once you have made the map visible to all, whenever another civ changed the terrain around their own homeland it showed up on everyone else's map. I presumed that the occasional lack of being visible was because an AI combat unit reset the flag.

"another civ changed the terrain" - do you mean terrain type or a terrain improvement?


Peaster said:
>Maybe you could also mention Historical Atze's trick for knowing the size of a stack.

I believe I did it. Do you mean another trick?

>Peaster said:
Related to that, you can sometimes see the top unit inside an opponent's city by right-clicking on the city. But I don't know the rule for when this is possible.

In my main post I said it can be seen from your city.
Is it not clear enough? or do you mean a unit may be visible even if there is no your own city nearby?


>Peaster said:
>Are you explaining when you can see an opponent's city ?

No, frankly said I didn't study this point. I only studied when UNITS are visible.

>But maybe you are referring to what you can see near one of YOUR cities?

Yes. "visibility of a city" is what a city (an imaginary guard on a highest city's tower) sees.

>Peaster said:
>I think you sometimes get different info about opponents' units from the world map and from the city map, but I'm not sure of the rule on this either.

I think on the city map you see only items that prevents a tile to be worked. Therefore on a city map you don't see allied units. Also you see a new foreign city even if it is not seen on a world map.

>Peaster said:
>...and I never saw the city until I activated the unit.

A unit sees another unit immediately, it needn't to be activated. I dunno how it works with cities... Need to be tested.

>You will sometimes know when the city grows [MP games] but not always [SP games?].

IMO you can see it only if you get fresh maps.
I must repeat my question: "Will Civ2 find out correctly who's map is more fresh?" In a savefile each civ has its own map, but not turns when each tile has been visited last. So if two civs are exchanging maps - how will Civ2 find out whose map is newer?


Edit:
testing...
when you can see an opponent's city
Foreign cities are spotted by units only after your unit is activated (according to unit's sight - 1 or 2). A city (an imaginary guard on a highest city's tower) doesn't see a foreign city on a world map, but it does see it on a city map (the foreign city blocks a production).
when you can see a change of tile's improvements
A unit must be activated in order to spot a new tile improvement. A unit needn't to be activated in order to spot a tile improvement has been pillaged (but the improvement must be in sight of the unit).

[SlowThinker]

Elephant said:
>>Whichever civ had a combat unit move through the tile last gets it's number recorded. If you are playing with "show enemy moves" set on, and you were the "most recently visited" (or you got a glimpse of other's maps from a map trade) you will see other civs units move into that tile

SlowThinker said:
>I believe this is a myth. I remember an old thread (maybe in the MP-forum, but I wasn't able to find now, it may be in archives already): some seasoned MP-player (rah?) claimed this myth too, so I ran some tests and it never occured.

Now I am not so sure about MP games. In past I tested it in SP (and it doesn't work), and I suggested that somebody tested it in MP, but IIRC nobody reported any test.
Only now I tested a MP game where I played alone, and it didn't work (no visible units on previously visited squares). And I think with more human players it should be similar...

[Peaster]

Originally posted by SlowThinker

>Peaster said:
Related to that, you can sometimes see the top unit inside an opponent's city by right-clicking on the city. But I don't know the rule for when this is possible.

In my main post I said it can be seen from your city.
Is it not clear enough? or do you mean a unit may be visible even if there is no your own city nearby?

I can often see the top unit in an AI/barb city, even if I have no city or unit nearby. This has happened in both SP and MP mode (with barb cities). I can't recall whether it has ever happened in a PBEM with a human-controlled city [I think so, but I can't reproduce it now].

Yes. "visibility of a city" is what a city (an imaginary guard on a highest city's tower) sees.

Maybe "visibility from a city" is less ambiguous.

I think on the city map you see only items that prevents a tile to be worked. Therefore on a city map you don't see allied units. Also you see a new foreign city even if it is not seen on a world map.

IIRC I have seen foreign units from the city map that were not visible on the world map, perhaps even still in blackness [this is consistent with your answer].

>You will sometimes know when the city grows [MP games] but not always [SP games?].

IMO you can see it only if you get fresh maps.

I guess "fresh map" means a map obtained from another civ ? In PBEMs, I can sometimes see distant cities change size, even without exchanging maps. Not sure of the rule, but it seems to work with allied cities, and not others.

Of course, you did mention HA's trick - my bad.

Maybe a little off-topic, but when does a city appear on your supply/demand screen ? My guess: when it's either

a) a capitol, or
b) visible on your world map, or
c) you have an embassy with that civ
AFAIK this is not related to alliances (?)

Also, is the city size on this report always accurate? I think the Top 5 Cities list is always accurate on size.