Main Page
Welcome to the explain xkcd wiki!
We have an explanation for all 2518 xkcd comics,
and only 38
(2%) are incomplete. Help us finish them!
Latest comic
| Sloped Border |
 Title text: "The slope will be 74° at ground level." "Okay, I think we can hack together a ... wait, why did they specify ground level? It's 74° everywhere, right? ... Oh no, there's a whole section in the treaty labeled 'curvature.'" |
Explanation
|
This explanation may be incomplete or incorrect: Created by a SUBSIDING GERRYMANDER - Please change this comment when editing this page. Do NOT delete this tag too soon. |
Nearly every single country (except some islands and Australia) demarcates an international border with other countries. The borders are established through law, treaty or consensus. Establishing an international border is assumed by present-day customs, immigration and security checks. Some countries (like Cyprus) have established a buffer zone in place of an international border to gain additional protection during a conflict.
In this comic, Cueball and Blondie established a "sloped" international border through a treaty. Usually borders are perpendicular to the ground so that all the air(space) above the ground belongs to the same country. This is called Air sovereignty. Thus it suffices to define the border on the earth surface, as 2D lines. The precise definition is that a line from the center of the Earth through the point of the border is drawn. Thus if the terrain is sloped then the border of the air sovereignty does form a sloped line with regards to the terrain.
If the borders were sloped (with respect to the horizontal ground level) an airplane would need to know its precise height to decide which country's rules currently apply. With the help of the Global Positioning System this would be in principle possible, although the height information of GPS is less reliable. (It might be possible to program a computer to use altitude data from the airplane's altimeter along with latitude and longitude data from the GPS to make an accurate determination.)
The mathematical computation for an angled air sovereignty seems relatively straight-forward and could be expressed with a single line of code or a single equation, although the people acting on the information are likely unfamiliar with code and equations and likely use tools with completely no support for sloped borders. How the line is curved (as indicated by the mention of curvatures in the title text) may make the issue very complicated. Does it continue towards the boundary of space strictly linearly? Or does it curve to follow a spiricular 'plane' as the Earth's surface (above which a position dictates an altitude) falls away beneath it through the Earth's roundness?
Likewise, while the comic doesn't mention this, such a curvature could be applied subterraneously (underground). This would then impact, at shallow levels, planning rights for property foundations and, at deeper levels, mining rights for minerals.
"GIS" refers to geographic information system, a tool for capturing and analyzing spatial and geographic data. People developing these systems would be inconvenienced by the border described in the comic.
It is possible this comic is inspired by such boundary disputes as the Beaufort Sea 'wedge' which, while in this case perpendicular to the surface, suffers from alternative interpretations of how to extend it from the shoreline out towards international waters.
Transcript
- [Cueball and Blondie are standing on a podium either for TV, or for the photo op when signing a treaty. They are holding a document together between them. In the background are two informational graphics. One intended to be cross-sectional showing a non-vertical dotted line between representative Cueball and Blondie figures, the other a skewed perspective of a similar setup but with two further figures and all but one these now positioned to be intersected by a 'shaded plane' effect so that some or most of their bodies are beyond the sloped boundary, as greetings of some kind are conducted through it.]
- Cueball: With this treaty, we are proud to announce the creation of the world's first sloped international border!
- [Caption below frame:]
- If I'm ever put in charge of a country, I'm going to spend all my time trying to think of new ways to make life a nightmare for GIS people.
|
|
This transcript is incomplete. Please help editing it! Thanks. |
Is this out of date? .
New here?
Last 7 days (Top 10) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
You can read a brief introduction about this wiki at explain xkcd. Feel free to sign up for an account and contribute to the wiki! We need explanations for comics, characters, themes and everything in between. If it is referenced in an xkcd web comic, it should be here.
- If you're new to wiki editing, see the explain xkcd:Editor FAQ for a specific guidance to this Wiki and the more general help on how to edit wiki pages. There's also a handy wikicode cheatsheet.
- Discussion about the wiki itself happens at the Community portal.
- You can browse the comics from List of all comics or by navigating the category tree at Category:Comics.
- There are incomplete explanations listed here. Feel free to help out by expanding them!
- We sell advertising space to pay for our server costs. To learn more, go here.
Rules
Don't be a jerk.
There are a lot of comics that don't have set-in-stone explanations; feel free to put multiple interpretations in the wiki page for each comic.
If you want to talk about a specific comic, use its discussion page.
Please only submit material directly related to (and helping everyone better understand) xkcd... and of course only submit material that can legally be posted (and freely edited). Off-topic or other inappropriate content is subject to removal or modification at admin discretion, and users who repeatedly post such content will be blocked.
If you need assistance from an admin, post a message to the Admin requests board.
