Bay 12 Games Forum

Comparing the one time I used the double-slit pumping method and when I tested doing the 2-(soil-)layer aquifer pierce with only 1 pick and no other embark items used, I'm going to pick cave-ins over pumping every time from now on. (A 1-z aquifer is even easier to pierce with a cave-in, but maybe not quite as safe if you're in a really hostile biome).

All that cancel spam...

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So, from the data we know that:

• There are set "target" maximum (daytime) and minimum (nighttime) temperatures.
• Heating is either sinusoidal or logarithmic, but cooling is linear.
• Daylight hours are a bit whack; if the hot edge of the map gets 16 hours of daylight, even if it's only at the summer solstice, that would mean the equator is actually still quite a ways off, and probably quite !!FUN!! (what's called a scorching desert in DF would probably feel refreshing after a walk at the equator).

I realized some erroneous assumptions/conclusions in my previous post (the short list of conclusions is above, but there's some other stuff too). First of all, cooling in itself isn't necessarily linear, but the effect of lower insolation late in the day (as the sun is setting) and the cooling has a total effect that looks linear. Or my new guess is that maybe the sun sets at around 13 hours of daylight (the cooling isn't completely linear before that, showing that there could still be some small heating), after which cooling is linear as speculated earlier. So the daylight hours are also a bit shorter at the South map edge, but still about an hour longer than expected for the equator, which should be a few minutes over 12h year-round (google e.g. "length of day Quito" or Singapore or something, check January&June). Also found this nice visualizer. 13 hours at summer solstice corresponds to about 17 degrees north, which would mean that the equator would still be somewhat habitable: at worst, only about as bad as the existing scorching climates.

As a side note, It's kinda annoying that the plateaus are so big, with enough accuracy (1 degree F or U should be enough, I think), there should be a curve visible over the whole day, or at most a couple of hours of even temperatures. In real life, you need averages e.g. off the same day every year for several years to get rid of weather effects, of course. Also, lack of a clear peak/trough means it's harder to pinpoint what kind of delay specific heat capacities introduce to the system.

Readings from a desert/rocky badland vs. ocean on the same latitude would be interesting, since it might help isolate the effects of latitude vs. surface material. The desert reading definitely suggests my "target temperature" claim from the quote above, since barring statistical flukes due to weather, you wouldn't get plateaus that flar in real life, pretty much ever, at least not at tropical latitudes. So yea, the temperature model is "broken", or to put it another way, pretty simple, and doesn't fully take into account how high temperatures can reach during the day and so forth. My guess is that the max. temperature plateau might actually a safety feature for gameplay, to prevent dwarves from melting in scorching climates. The low temperature plateau is probably a "minimum ambient temperature" defined by latitude and/or biome, that cooling occurs to.

Regarding the temperature plots from Phoenix, yes, temperature does flatten out a bit especially on warm days, but I'm not totally convinced by the examples yet, either. Like I've said, one, or a few, days do have slight weather fluctuations even in a desert with little to no "weather" as usually defined in temperate zones (rain, clouds, etc.). Also, the y-scale is really flat in those plots, leading to an illusion that the temperature is more even that it is. Possibly.

Oh, and we have different energy units because the calorie was probably invented first; it's pretty easy to define experimentally, you just need a heat source, a thermometer, and a scale (to measure how much water there is), and a closed water container to prevent evaporation. However, it's not a neat, SI, base-10 unit, unlike the Joule. Why are there (in the imperial system, of which "you Americans" are the last big die-hard users) so many arbitrary units of distance/time? At least the calorie is somewhat scientifically defined.


...and finally, regarding the 2nd sand desert plot, yea, I'd say the "hump" is a feature of the heating model. Either the insolation function only approximates a sine curve with linear segments, or the temperature curve is formed directly, and the slope of temperature increase is just set to drop by some % 3 hours after sunrise.

wierd: A Joule (J) is 1 kg * m² * s^-2. You're thinking of calories: 1 cal is about 4.2 J, 1 Cal or kcal about 4.2 kJ.

Also, I'm kinda skeptic about some of your claims about the plateaus making sense. Ocean water is pretty stratified, with only limited mixing between layers. For a very simple model, heat is transferred between layers and between the surface&atmosphere by heat transfer rate being relative to the temperature difference (for pure blackbody radiation/absorption, it would actually be the Stefan-Boltzmann law i.e. the difference between the 4th powers of the temperatures), so that cooling/heating is always fast at first and then slows down.

Well ok, the plateau makes sense, since the later slow cooling/heating could indeed look like a plateau, but it should be symmetric, not asymmetric as with the data. The plots look more like heating is just turned off at dusk, and the temperature drops linearly, as itg said. Also, whereever the measurements were made, it was (or should have been) summer at the time, since dusk occurred 16 hours from dawn. Also, on Earth, a daylight duration of 16 hours at summer solstice corresponds to roughly 48 degrees North/South. Which is a bit south of Paris, about the same as Munich, Vienna, Ulanbaatar, or a tad North of Seattle. Or about 150km South of New Zealand's South Island (pretty much open ocean all around the Earth, with the exception of southern Argentina/Chile).


Since insolation follows a sinusoidal curve over the day, I'd claim that average daily temperatures (so excluding weather effects, which DF doesn't have AFAIK) are also nearly sinusoidal, e.g. with this plot of water temperature over a year (the yearly plot is analogous to a daily one, which I had trouble finding just now).

What the large heat capacity or specific heat capacity (2 different things) does is delay the increases/decreases in water temperature compared to the insolation maxima/minima: solar heating is at it's smallest at the end of December, and at it's greatest at the end of June, and yet in the above "warm" coastal area water temperature plot, the sea water reaches it's temperature minimum in late January/early February, and it's maximum some time in August. The greater the specific heat capacity of the material, the bigger the delay. And if we include mixing/conduction of heat deeper into the material, the heat capacity and thus the delay grow. A sand desert (which also transmit heat downwards into the earth really badly, IIRC) would react quickly to changes in solar heating, both over the day and over the year, whereas oceans are pretty much the slowest thing to do so found on earth (possibly beaten at times by moist forests, both tropical and temperate).

So, from the data we know that:

• There are set "target" maximum (daytime) and minimum (nighttime) temperatures.
• Heating is either sinusoidal or logarithmic, but cooling is linear.
• Daylight hours are a bit whack; if the hot edge of the map gets 16 hours of daylight, even if it's only at the summer solstice, that would mean the equator is actually still quite a ways off, and probably quite !!FUN!! (what's called a scorching desert in DF would probably feel refreshing after a walk at the equator).

I have a corpse and several teeth of a dwarf lasher (even has a goblin name and everything) that came with a siege lying about, that's not getting moved to a refuse stockpile either. I think I had coffins available, but not sure. The FUN side is that non-fortmember dwarves will still become ghosts.

Quote from: Snaake on September 23, 2013, 01:23:55 pm

To be specific, (at least this is what I've been told), station orders are treated as "stand within 3 tiles of this spot". So if your danger room is 1x4, you could order them to station themselves at the far end. Assuming you don't have corridors immediately to the sides, or dug out space behind the danger room.

I thought it was 7. That's why I always make mine 7x7.

Well, "within 3 tiles" (including the 3rd tile) translates to a 7x7 room, if you order them stationed in the middle. 4x7 or 4x4 would be ok sizes too, besides the 1x4. You just have to have solid stone/soil (for 3 tiles) behind the walls that the "station point" is adjacent to.

If it was 7, you'd need a 15x15 room to be able to station them in the middle.

For fast training, you want 2- or 3-dwarf training orders (doesn't have to be 2-3 dwarves per squad, you can assign multiple 2- or 3-dwarf training orders to larger squads), OR you want the squad leader to have high skill and high teacher skill to begin with. Best way to get that high skill is to preferably embark with a couple of dwarves as proficient teachers, but they'll also skill it up with time when sparring (when they do demonstrations in between).

If you don't believe me, dig up the science thread on teacher skill; it's a must-have if you want demonstrations to be any use, but training with it does go faster than just sparring, especially when it comes to dodging/armor user, which sparring doesn't raise so quickly.

Also, I was sending my melee (10-15 melee, 4-5 marksdwarves) out to fight sieges with just bronze weapons, helms, wooden shields, leather/bronze boots and maybe a bronze chain shirt when they were about 50/50 legendary and sub-legendary (10-14 skill). Marksdwarves didn't even have that much armor or skill. No casualties from combat, a few arm/leg injuries. Weapons and shields (wood is just fine!) are always my first priority, then a metal helm, after that everything else can wait a while, a low-quality copper/bronze/iron mail shirt or even leather armor isn't that hard to get though. Also, bone greaves and gauntlets, if you don't feel like smithing yet.

Kept losing a cart in the trench.

If by "losing" you mean the bug where they still appear in stocks screen, then yea, that's probably because it's being pushed by fluid movement. Which really just sets an upper limit on the throughput you can have, i.e. how often a cart can go into the magma trench, since the trench needs to have time to fill before it's safe for another cart to enter. I did "lose" a couple of minecarts, because I initially tried to use nethercap ones, but while nethercap is magma-safe for pumps etc., if it's submerged in magma it gets destroyed anyhow, since only certain items like anvils and screw pumps can be magma-safe.

Btw, at least for stuff that got "lost" in my river and moat like that, marking for dumping from stocks screen allowed my dwarves to carry them out, even though they were invisible to loo(k). After the river and moat were drained, of course. Or dfhack autodump works too.

Why aren't my dwarves butchering the Giant snails/louses/ticks/thrips I've caught with cage traps?

They've hauled them to an animal stockpile (no stockpile is set to give to the butcher, doesn't make sense and there's usually no need to do that with the butcher's workshop anyway), I've set the butcher order from status-animals, and while my dwarves are busy doing post-multisquad ambush cleanup at the moment, I do have butchery enabled on a dozen dwarves, many of whom were idling prior to the ambush.

They butcher domestics fine. The only difference I can think of is that the above giant bugs are still wild. However, I did try taming a giant snail earlier to see if that would work, but the dwarves refused to butcher it for a year or more after that, too. Also, built/unbuilt cages seem to be the same. And I can't really pasture them safely without taming them first.