View source for 2519: Sloped Border

{{comic
| number    = 2519
| date      = September 22, 2021
| title     = Sloped Border
| image     = sloped_border.png
| titletext = "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==
{{incomplete|Created by a SUBSIDING GERRYMANDER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Every single country demarcates an {{w|international border}} with other countries. The borders are established through law, treaty or consensus. Establishing an international border is very necessary for customs, immigration and security checks. Some countries (like {{w|Cyprus}}) have established a {{w|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 {{w|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 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 {{w|Global Positioning System}} this would be in principle possible, although the height information of GPS is less reliable.

The mathematical computation for an angled air sovereignty seems relatively straight-forward and should be expressed with a single line of code. However, 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?

"GIS" refers to Geographic Information Systems. 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 {{w|Territorial_claims_in_the_Arctic#Beaufort_Sea|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.]
: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.
{{incomplete transcript|Do NOT delete this tag too soon.}}
{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Blondie]]
[[Category:Multiple Cueballs]]
[[Category: Geography]]