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For sentient avians, knowing the location and behavior of currents in the air would be vitally important. Jet streams, thermals, downdrafts, and shear layers would all be important in their daily lives.

I imagine that bird people would want to map these currents. While they might change on a daily basis, common maps of persistent features in a landscape, as well as up-to-date maps of specific features in real time, would be incredibly useful for planning movement and navigation. Merchants and armies, in particular, would be highly reliant on these maps for planning logistics. The difficulty in doing so is that air currents are three-dimensional, and any map of these currents must be capable of informing its user as to the three-dimensional nature of these phenomena.

What would be the best way to create these maps? Obviously, how to display such maps will depend on the technology level of the avians, so for the purpose of this question, how would a race of avians with rennaisance-era technology map the atmosphere?

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    $\begingroup$ One element is that being avians, they might, in the same way than actual birds, "feel" the currents. And understanding the fluid mechanics required for "simulating" currents is beyond their level. At the end, they probably would be good enough making surface maps, with emphasis on mountain ranges. $\endgroup$ – clem steredenn Jun 10 '15 at 19:12
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    $\begingroup$ @bilbo_pingouin Avians feel the air currents except, of course, the penguins ;) $\endgroup$ – Samuel Jun 10 '15 at 19:58
  • $\begingroup$ @Samuel indeed. But then they don't need maps of the atmosphere. $\endgroup$ – clem steredenn Jun 10 '15 at 20:03
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    $\begingroup$ You know, I don't think it is practical to read a map while flying for an avian, so in practice they'd probably use something like memorized songs of flight paths between waypoints. Such descriptions of routes are what navigators used to use as well. Birds also follow paths from waypoint to waypoint IIRC. $\endgroup$ – Ville Niemi Jun 10 '15 at 23:10
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    $\begingroup$ @O.R.Mapper Well, if you drive alone you stop. With a map reader or navigator you do not. Good point with the stop/brief landings though. Even avian maps would probably be built from the view point of some discrete stopping points, not as continuous expanses like most maps we use. $\endgroup$ – Ville Niemi Jun 11 '15 at 17:34
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Maps

They would probably use something similar to our pilots. A winds aloft map. These maps describe the prevailing wind.

While wind from moment to moment can be going many different directions, that's mostly only true very near the ground. Away from the ground the winds are much more consistent and powerful (this is why wind turbines are built to be so tall).

These maps describe the winds at typical flying altitudes (for small planes flying <10k feet), and that works because realistically your avians probably won't occupy very much vertical space for normal flight. If your avians desire further precision in the vertical dimension, then stacking symbols of a different color to represent higher altitude winds would be a simple addition (which I've created below by merging two days of winds aloft maps). You would obviously want higher spatial resolution depending on the range of the avians, but the idea is the same, just imagine a tiny Alaska shaped island ;)

enter image description here

The symbols describe both wind direction and strength with these little symbols (called a wind barb).

Measurement

As for measuring these winds, without satellites, radios, or other electronics the avians would need to send out scouts to measure it by... wing. The avians could carry devices to measure the wind speed, either simple anemometers or even just a plain old wind sock. By hovering over a single spot they can take measurements and then repot them back to wherever the charts are being made. Their altitude during measurement will need to be estimated from experience or using the old thumb (or talon) method against objects on the ground.

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Why would they need three-dimensional maps? Regular maps will be sufficient for what they need.

Assuming the sentient avians descended from not-so-sentient avians, detecting local air currents should be very natural to them. Many of the things that might concern them, such as thermals and downdrafts, wouldn't be worth putting down on a map. You could mark on a map if there's a spot with particularly good updrafts or dangerous downdrafts, but there's no need to specify exactly how high they are - the specifics are likely to change enough to make detail on a map unhelpful. In general, local phenomena will change enough to make their instincts beat out what a map may say.

I doubt they'd need maps for jetstreams, either. On Earth, polar jetstreams are usually "7 to 12 kilometres (4.3 to 7.5 mi) above sea level", and subtropical jetstreams are usually "10 and 16 kilometres (6.2 and 9.9 mi) above sea level". Some geese have been reported to fly over Mount Everest (so about 9km), but even those geese try to stay closer to a 5.5km height. So it's unlikely that the jetstreams will be a major concern for your avians - even if they can get up there it'll be too high for them to stay in the jetstreams for more than a little while.

So what would their maps look like? Pretty much like our maps, except with more notes about the air currents. Like @Samuel mentioned, any notes would be about the prevailing wind conditions, but I think they would be much less detailed than the maps our pilots use - again, the avians would be relying heavily on their instincts. If there are places where the air currents are unintuitive to them, they'd make note of those, but otherwise the general shape of the land would be enough detail to allow them to know what flying conditions will be like.

Something you could take a look at would be maps of ocean currents. They'd probably have something like that to help show what the best paths for travel are. Additionally, they'd either have different colors/markings or multiple maps to account for seasonal variations.

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Maps

I made a partial example map for the birds of a land called Tjerokya. It uses (crude) arrows to show the path of currents traveling across the land and sea. Indicating changes in three dimensions is harder, so I used colors to describe the changes. Redder colors mean rising currents, and bluer colors mean sinking currents (yellow and green are near the middle).

There are two additional features I didn't implement here:

  • Wind speed. Longer arrows can be used to indicate faster winds.
  • Altitude. Simply use thicker arrows to indicate higher elevations.
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Like this (Very Rough Example - a picture is worth a thousand words). Explanation is after the picture.


Example of map


This is a map drawn to represent a certain section of canyon. The two thickish curvy lines represent the cliff sides of the canyon. Circles with "X" inside represent other obstacles such as pillars in the canyon.

Each line that has arrows attached to the end represent the direction of a wind current. For example, in this current map, there are 4 lines that are "inside" the canyon, with 3 arrow pointers, and one line that is in the center with only 1 pointer.

The arrow pointers could be what the Avians use to determine wind strength - the more pointers, the higher the wind speed. Eg: each pointer is 25 kph (or any other value you choose). Following this map, the Avian reads: Oh, there are currents going in that direction that go at 75kph. There is also one that goes at 25kph.

But air is 3d. How do we know what level the wind is at? I draw attention to the numbers near each line. Of course, when the Avians do this they'll probably use a different color for the numbers, but the numbers represent a "depth" level. Perhaps 0 being ground level, and every increment of 1 is 50m.

Reading this map, you can see that the currents at the bottom of the canyon (approx 150m down (negative 3)) are at 75 kph, and the currents at 50m above the canyon are only at 25 kph. There is a current to the right of the canyon 200m up that goes at 25 kph.

But what about updrafts? Those are important for lift! Please see the sections on the map labled "UD L:X" where X is a number. It may be hard to see, but I did my best to draw a dotted line area around it. Those areas are "updraft" areas, vertical lift providing areas. UD stands for Updraft, and the Avians could use DD for downdraft (if that exists), etc etc. It's just to denote certain large areas of lift manipulating currents. L:X stands for the amount of lift they'll get. A higher number represents more lift, and lower is less. Note: the numbers I've picked for this map so far are arbitrary and you can use what you want - perhaps the maps can even include a legend and scale on the side that show windspeed/strength.

Of course, when the Avians do this they'll have colors to represent landmasses and ocean, etc, instead of doing it on crappy office lined paper...

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You would need three dimensional models if we are talking Renaissance.

I imagine levels of maps here.

Level 1: Global

Create a wire frame globe and plot the prevailing winds with some sort of thread. The thread could be attached to a sliding mechanism attached to the wire frame to allow for adjustments. This map wouldn't need to change often. You could create something like this and put in in the center of each town to make it readily available for people enter image description here

Level 2: Consistent winds

This would be on a more local scale but cover the same types of winds as level 1. Mainly meaning winds that don't often change. Currents off the oceans or seasonal winds for example. The main difference here would be how localized the area is. A cube frame for the local regional air space would fit into this category.

Level 3: Local winds with local events. Thunderstorms or the gusts from forest fires would fall into this category...this would be tough to maintain and distribute. Predominantly I think this would be handled by instruments rather than maps...it just changes too quickly. In a computerized age you could probably pull it off but with renaissance tech you are probably going to need a lot of wind socks and wind speed gauges around town and along major travel paths.

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While sentient avians would definitely make some note of winds aloft, there are other types of maps that are needed for safe flight as well. A map of ground features themselves, such as found on a sectional chart, is not only useful for figuring out where to park yourself overnight when a storm is coming in while, but for orienting yourself and navigating while in the air, especially over unfamiliar terrain (this is known as pilotage, and is taught to all airplane pilots as part of their fundamental flying courses). More sophisticated sentient avians who have developed or evolved blind-flying systems could have route maps and such that work with those waypoints, similar to today's en route instrument charts.

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A map depicts a thing as it relates to another thing. Travelling in a car the other things are now exclusively visual landmarks on the ground. Humans used to use other things: the smell of the air, the temperature of the water. Sailors used the nature of the wind and appearance of the clouds.

Some avians are thought to have a magnetic sense and use that to migrate. Avians might also have an internal altimeter.

We think of a map as fixed: it shows what is. I like the idea of the "map" being variable depending on season, prevailing weather, the actions of other things in the environment. Possibly other things even less perceptible to humans like telluric currents which could be perceived by animals with magnetic senses. Reasonable beings would debate about which map was most appropriate for a given time. I am certain exactly these debates take place among sailors today.

/ they'd probably use something like memorized songs of flight paths between waypoints. Such descriptions of routes are what navigators used to use as well. Birds also follow paths from waypoint to waypoint IIRC. – Ville Niemi/

I like the idea very much of a map being a song. Different verses correspond to different situations, with the chorus marking the individual song. That would be fun to write too! The debate would be sung back and forth. 40,000 years ago I suspect most accumulated human wisdom was as songs. This is why even average humans are able to remember the tunes and lyrics from thousands of songs.

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