Which SI Prefixes does KSP Use? When do Unit Transitions Occur?

[richfiles]

I was wondering which SI prefixes KSP uses in game, and are there any that are skipped? I ask because I know it skips km on your altimeter... (I'm so wrong! i guess I must typically timewarp from LKO to any other body and never noticed Km before! LOL  ). It just goes from counting hundreds of thousands of meters and then rolls over into, if I recall correctly, Megameters. After that, I know I've seen Gigameter measurements before in the map views. Does KSP skip any other units than km, or is it just that one unit that gets skipped? I think I recall seeing km used in map view for distance to target, and in standard view to show distance to other objects. I just don't know if km is used for any orbital data... Altitude, Apoapsis, Periapsis, etc.

I'm currently in the process of building a digital orbital data readout to fit into a larger scale custom controller for the game. I'd like to keep the units displayed on the controller matching the units displayed on screen. It'd be disorienting to have my readout show 100 km, and the altimeter on screen say 100000 m. I know they are the same, but it's not consistent. I'm occupying myself with continuing my controller build, since my motherboard unfortunately died. It's hard to run KSP to check for units of measure when your computer ain't even functioning.  Who knows... Maybe I can get some progress in before the motherboard is repaired/replaced.

Adittionally, I also wonder how high do the SI prefixes go? I want my readouts to go as high as they need to go to cover whatever KSP can throw at it...

m, km, Mm, Gm, Tm, Pm, Em, Zm, Ym... What's the largest SI prefix KSP actually supports? Are there any other prefixes that KSP tosses out due to the number of digits the altimeter displays? Does the map view use km for any orbital characteristics? I got some nice 14 segment alphanumeric displays that are smaller than my main numeric displays. They are at the end of each relevant numerical display, and will show the correct SI units. I can make the displays support all units (as well as "m.S" and "ΔV"), but it will require more work to add the extra characters. Don't ask me why, but I'm doing a diode matrix ROM for them. It'll be kinda retro, but extra work to have extra characters supported. So... yeah... Just curious if I should plan on supporting them?

Thanks in advance.

*UPDATE*
So, apparently, I am just blind. I never noticed the use of Km as an altimeter measurement, likely cause it occurs in a range that I rarely orbit at (or stay at for long). I can salvage this post though, as now I need to catalog the transition points. Where does KSP switch from m to Km, Km to Mm, Mm to Gm and so on. When I get my motherboard back from being serviced, I'll fire up KSP and check it out, recording the transition points here (unless someone beats me to it).

Edited February 9, 2017 by richfiles
Edited because I herp the derp professionally. 9_6

[rudi1291]

What the altimeter actually tries to do is to fill its 6 digits and then put the SI prefix behind that number that fits. Thats why there is no "km", its not skipped. The map view doesn´t really use SI prefixes. It just uses meters for altitude and km for distance

Edited February 5, 2017 by rudi1291

[richfiles]

I suppose to play it safe, I should just encode all the SI prefixes in the hardware. At least then, it's easy to let software sort it out.

[Nathair]

16 hours ago, richfiles said:

I was wondering which SI prefixes KSP uses in game, and are there any that are skipped? I ask because I know it skips km on your altimeter

It "skips" deca- and hecto- too.

[MinimalMinmus]

Yotta is the last official large SI prefix.

However, you may notice how,starting with Tera there is a pattern of linking it with the n of the 10^(3n) the prefix represents:

4: tetra=Tera 

5: penta=>Peta

6: hexa=> Exa

7: hepta => Zetta ( this one also comes from the greek letter)

8: octa => Yotta

Also, Z and Y is the beginning of the reverse alphabetical order, so the most popular choice for 10^27 and 10^30 are respectively "Xena"(ex: Xm) and Weka (ex: Wg).

Edited February 6, 2017 by MinimalMinmus

[richfiles]

Well, I built it! I ended up encoding all the following SI prefixes, m, km, Mm, Gm, Tm, Pm, Em, Zm, Ym, m.S, ΔV, --, as well as an all segments test character. I decided to play it safe and encode everything I might need, so it's there if I ever do need it. It's a 270 bit diode ROM matrix (100 ones, 170 zeroes). It has 30 LED segment outputs, and 13 inputs, to select each of the desired characters. I appreciate the information I got here. It certainly helped me decide to play it safe.

The highest distance I think I've ever seen in a YouTube video I think ended up being Yottameters, and the game was getting pretty glitchy by then, if I recall. All in all, I don't think the game even could go higher than that, due to floating point rounding errors. These available units ought to be able to cover anything KSP throws at my controller.


Here's what the diode ROM actually looks like. It took all afternoon and evening, but I finished it! It mounts directly behind the LED displays.

Again, thanks for the advice and suggestions. 

Edited February 14, 2017 by richfiles

[cantab]

On 05/02/2017 at 10:10 AM, richfiles said:

I ask because I know it skips km on your altimeter... It just goes from counting hundreds of thousands of meters and then rolls over into, if I recall correctly, Megameters.

Incorrect, it shows K when that's appropriate. Example: https://flic.kr/p/RBth3s (in RSS, but it'll show in stock too.)

I think the largest I've seen is Y. But I doubt anything beyond T will appear without glitches or cheats, considering 100,000 Tm is about 10 light years. (That said, I've not been in interstellar space in the Galactic Neighbourhood mod).

[richfiles]

Well I'll be a Kerbal's uncle! A big fat "K" on the Altimeter! You're right! I suppose part of the reason for not noticing it, is that I spend most of my time either in LKO, or shooting out to Mm and Gm ranges via time warp.

In light of my lack of perception, It now occurs to me that I'm going to have to carefully profile KSP's altimeter units display. Also, fortunately, i finally got a response on my motherboard RMA. I'll have to pay, cause I'm out of warranty, but It's worth it to be up and running again! I'll have to just record in detail when KSP likes to do it's altimeter units switches, and program my controller to match the switch points.

And you prove why it was indeed wise to encode ALL the primary SI units on my hardware!