Traveller mapping conventions (islands)

[rancke]

A Traveller map has 500 hexes. I've just been doing a bit of work on the map of Heya. According to canon it has a hydrographic percentage of 70, or 150 land hexes. It has one sole continent which (I've calculated) covers about 72 hexes (give or take). So I need to come up with enough islands to cover 78 hexes (give or take). Which brings me to my question: How large, how many hexes, can an island be and still not be a continent? Are there any rules of thumb, definitions, anything like that?


Hans

 

[DickNervous]

Well, if you use Earth as an example, it would have to be as large as Australia to be considered a continent. According to Wikipedia
Australia is 7.6m km² and is 3x the size of Greenland which is 2.138m km².

Heya is size 6 which means it has a diameter of 9,600 km.
Surface area (SA) of a sphere = (pi)*d².

So Heya has a SA of (pi)*9600²= pi * 92,160,000 = 289,529,178km².

Divide that by the number of hexes (500) and each hex is 579,058 km². So Australia would have an area of about 13.12 hexes . Assuming I did the math right, if you keep the islands smaller than that nobody could contest that they are actually continents.

To be completely honest though, on a planet that is 70% water and has a primary landmass that is 41,692,120 km² I would say that anything less than 1/3^rd that (or about 24 hexes) could be considered an island.

 

[Timerover51]

Heya is size 6 which means it has a diameter of 9,600 km.
Surface area (SA) of a sphere = (pi)*d².

So Heya has a SA of (pi)*9600²= pi * 92,160,000 = 289,529,178km².

To be completely honest though, on a planet that is 70% water and has a primary landmass that is 41,692,120 km² I would say that anything less than 1/3^rd that (or about 24 hexes) could be considered an island.

Since that primary land mass is 14.4% of the surface area, the remaining land masses, assuming that you count the ice caps as part of the hydrosphere, total roughly 16%. The combined land area of Asia, Africa, and Europe is about 16.6% of the Earth's surface, so you have quite a bit of land area proportionately to account for. Australia is viewed as a continent with 1.5% of the Earth's land surface.

This would mean that a land area one-tenth the size of the primary continent would be only slightly smaller proportionately than Australia. I would say that would rate as a continent. For something to be called an island, it should be no larger than about 0.5% of total land surface. That does give you quite a few islands to put on a map.

 

[DickNervous]

Since that primary land mass is 14.4% of the surface area, the remaining land masses, assuming that you count the ice caps as part of the hydrosphere, total roughly 16%. The combined land area of Asia, Africa, and Europe is about 16.6% of the Earth's surface, so you have quite a bit of land area proportionately to account for. Australia is viewed as a continent with 1.5% of the Earth's land surface.

This would mean that a land area one-tenth the size of the primary continent would be only slightly smaller proportionately than Australia. I would say that would rate as a continent. For something to be called an island, it should be no larger than about 0.5% of total land surface. That does give you quite a few islands to put on a map.

He can also make that primary land mass a little bigger as well, unless the size is already defined somewhere.

 

[rancke]

Since that primary land mass is 14.4% of the surface area, the remaining land masses, assuming that you count the ice caps as part of the hydrosphere, total roughly 16%. The combined land area of Asia, Africa, and Europe is about 16.6% of the Earth's surface, so you have quite a bit of land area proportionately to account for. Australia is viewed as a continent with 1.5% of the Earth's land surface.

Yeah, it's quite annoying. I've been working on a couple of adventures and a writup of Heya for quite a while now, and I've concentrated exclusivly on the continent. I've been thinking in terms of a few islands and archipelagoes that would, because of Heya's tech level, be pretty much ignorable. And then I decide to figure out how much of the land area the continent covered and find that I have yet to deal with half the world.

I guess I can say that the rest of the land is very sparsely populated, but still...

This would mean that a land area one-tenth the size of the primary continent would be only slightly smaller proportionately than Australia. I would say that would rate as a continent. For something to be called an island, it should be no larger than about 0.5% of total land surface. That does give you quite a few islands to put on a map.

We do have some pretty big islands (two and three hexes) on Regina.

EDIT: I'm wrong there. The big ones are one to one and a half hexes. And the smallest continent on Regina is six hexes.

He can also make that primary land mass a little bigger as well, unless the size is already defined somewhere.

It is. The continent is said to be the sole continent and to be 10,000 km across (at its widest point, that is).


Hans

 

[flykiller]

continents ride on continental plates. some islands, such as japan and the malays, are uplifts of one sort or another. other islands are strictly vocanic, such as hawaii and iceland. some "islands" are actually part of a larger continental shelf, such as madagascar and england.

 

[Timerover51]

He can also make that primary land mass a little bigger as well, unless the size is already defined somewhere.

Nothing shows up in the Wiki regarding sizes of continent. Maybe something in the Fifth Frontier War game?

 

[DickNervous]

It is. The continent is said to be the sole continent and to be 10,000 km across (at its widest point, that is).

The continent is 10,000 km at it's widest point just means that it can only be 9,999 km wide everywhere else. it could be 10,000 x 9,500 and take up 95,000,000 km² which would be 32% of the surface.

 

[rancke]

The continent is 10,000 km at it's widest point just means that it can only be 9,999 km wide everywhere else. it could be 10,000 x 9,500 and take up 95,000,000 km² which would be 32% of the surface.

The continent is described as "roughly handshaped (with six fingers) and is 10,000 km across at its widest point".

I have expanded that to it being created by a meteor impact long ago. The first and sixth fingers (top and bottom thumb) are part of the crater rim. The continent is tilted so that the eastern end is highlands and the western end is below the sea (with the four middle fingers extending out into the sea).


Hans

 

[rancke]

Nothing shows up in the Wiki regarding sizes of continent. Maybe something in the Fifth Frontier War game?

It's from the amber zone/adventure The Ship in the Lake by Loren Wiseman in JTAS2, expanded upon in The Traveller Book.


Hans

 

[simonh]

The continent is described as "roughly handshaped (with six fingers) and is 10,000 km across at its widest point".

There's nothing to stop it being longer than it is wide, just like a hand. That description is pretty vague and open to a wide latutude of interpretation

Simon Hibbs

 

[Shonner]

I don't shape/arange my land masses to fix the hex shapes. The hex map is just an overlay no matter the land features/types.