Graphs of Maximum Elevation by Inclination

[SunJumper]

A lower safe altitude caused by resonance between the orbit and the body's rotation would require a specific longitude of ascending node.

[Cryphonus]

How did you make those charts?

It's a bit weird to see so many flat lines, no? I guess the KSP engine is cheating when making terrain (for performance)..

And I don't see why the altitude always go up with inclination...

Flatlines are a bit weird i agree. Even though you are getting the data for a single degree, there should be altitude elevations for every inclination on a planet as long as they are not totally flat, this is true for calculating maximum altitude too. Say you have a maximum altitude of 4000 meters at 45 degree inclination. What are the odds that 4000 is again the maximum altitude at 55 degree inclination?

I think you made a mistake and assumed that the planet is motionless while you are orbiting at a non-zero inclination.

[alterbaron]

Flatlines are a bit weird i agree.

Here's why the flat lines happen (assuming I understand the plots correctly):

Since the planet rotates under your ship while orbiting, an inclined orbit will, in the worst case, bring you over every piece of land within some interval of latitude centered on the equator.

The maximum elevation by inclination is then determined by the highest point in this region.

It will stay constant until the region grows to include a new, higher point, at which point the maximum elevation will jump to this new value and stay there. (Until the next higher point is included and so on.)

Edited August 29, 2013 by alterbaron

[Jackissimus]

Here's why the flat lines happen (assuming I understand the plots correctly):

Since the planet rotates under your ship while orbiting, an inclined orbit will, in the worst case, bring you over every piece of land within some interval of latitude centered on the equator.

The maximum elevation by inclination is then determined by the highest point in this region.

It will stay constant until the region grows to include a new, higher point, at which point the maximum elevation will jump to this new value and stay there. (Until the next higher point is included and so on.)

That's exactly right.

I wonder how the charts were generated and if they include the procedural craters on Mun for example. IIRC MapSat has trouble detecting them.

[tavert]

My best guess:

Elevation data from http://forum.kerbalspaceprogram.com/showthread.php?p=307335#post307335 (scroll down for link to Map Data)

Take maximum along each latitude

Take cumulative max from 0 to (+/-) each inclination

Since kerbalmaps itself seems to resolve the craters quite well, that indicates saik0's custom plugin that he uses to collect his data includes them. I imagine the problem with MapSat is just resolution. If you save the MapSat data to a csv and collect for a long time, I bet you'd be able to make them out. This isn't the most efficient way of doing things though, since you don't have too much control over where your sample points are taken. saik0 can probably sample directly at the uniform grid of points he wants, without needing to do much post-processing or resampling.

[Cryphonus]

Here's why the flat lines happen (assuming I understand the plots correctly):

Since the planet rotates under your ship while orbiting, an inclined orbit will, in the worst case, bring you over every piece of land within some interval of latitude centered on the equator.

The maximum elevation by inclination is then determined by the highest point in this region.

It will stay constant until the region grows to include a new, higher point, at which point the maximum elevation will jump to this new value and stay there. (Until the next higher point is included and so on.)

You explained this so much better than me! OP if you want to generate this graph without the elevation errors you should generate them from a static elevation map. Or you can try to stop the planets rotation....

[lazarus1024]

Interesting that all of the bodies have their highest point by the poles.

I wonder what the math would be on the various bodies for what the lowest energy burn to orbit would be taking in to account rotation of the body and dV then required to leave the SOI of the body.

[Tiron]

Interesting that all of the bodies have their highest point by the poles.

I wonder what the math would be on the various bodies for what the lowest energy burn to orbit would be taking in to account rotation of the body and dV then required to leave the SOI of the body.

Some places do have high elevations at the poles, but what you're seeing here is mostly just the effect of flying over more of the surface. For inclinations of 90 degrees or less, your orbit will take you back and forth between the Northern and Southern Latitude equal to your inclination. So if you're in a 30 degree orbit, you're going to be bouncing back and forth between 30N and 30S, potentially flying over a third of the planet's surface. If you increase to 45 degree inclination, you're now flying over half the planet's surface, including the bits from the lower inclination orbit. So the maximum possible elevation can only either increase or remain the same as the inclination increases.

Barring orbital resonance effects that keep you from passing over parts of the surface, but that's highly dependent on altitude and would make for one heck of a complicated graph.

[Stargate525]

But it would be VERY interesting to see if, for example, there's a way to find a 4,200m safe orbit on Dres that's incline 80 degrees, and just happens to skirt the mountains.

[lazarus1024]

Some places do have high elevations at the poles, but what you're seeing here is mostly just the effect of flying over more of the surface. For inclinations of 90 degrees or less, your orbit will take you back and forth between the Northern and Southern Latitude equal to your inclination. So if you're in a 30 degree orbit, you're going to be bouncing back and forth between 30N and 30S, potentially flying over a third of the planet's surface. If you increase to 45 degree inclination, you're now flying over half the planet's surface, including the bits from the lower inclination orbit. So the maximum possible elevation can only either increase or remain the same as the inclination increases.

Barring orbital resonance effects that keep you from passing over parts of the surface, but that's highly dependent on altitude and would make for one heck of a complicated graph.

*facepalm* sigh, I was totally reading the graphs wrong. I was looking at it as the maximum elevation AT those lattitudes, not the maximum altitude at an orbit of that inclination. My bad.

Still, a few of those moons/planets have their highest mountains relatively close to the poles.

[Dweller_Benthos]

Sounds interesting, but I just get the time out error in both chrome and firefox. Overloaded server?

[loknar]

somehow I can't open this page on chrome (OSX) I get a timeout error. but it works in firefox. just fyi. If you need a diagnostic let me know

http://www.kerbalmaps.com/charts/elevation_inclination/

[Vector]

Very cool idea. May be handy for searching for anomalies or something.