Topic: mismatched map scales ?

[MisterK]

The global world map found in the SWMA4 has a scale of 1 cm = 300mi. Which, if we consider that the global map shows a bit less than the full "western" hemisphere, makes for a kulthean circumference slightly greater than 28900 mi.

Which is OK, since the master atlases also indicated that Kulthea is "slightly larger than earth" (and earth equatorial circumference is roughly 24900 mi). SWMA3 provided the Kulthean diameter at 8600 mi, for a perimeter of about 27000 mi. Not exactly the same, but close enough - it can be explained if we assume that the map distorts scale a bit in the equatorial band (its shape would suggest so).

With this scale, Jaiman is about 1800 miles from extreme north to extreme south, and 2150 miles from extreme east to extreme west.

But the scale of the Jaiman map found in "Jaiman, Land of Twilight" puts Jaiman around 1370 miles East-West and 1160 miles North-South. This is the same scale as the partial map provided in the back of Haalkitaine book.

However, if we assume this scale is right, then the "global map" would be 9230 miles from east to west, which would make for an equatorial circumference of around 18500 mi, which is significantly *smaller* than earth's. It would make for a roughly 5900 miles diameter, which is about halfway between Earth and *Mars*.

I can only assume that the scale of the Jaiman (and Haalkitaine) map is wrong, but the phenomenon is not isolated.

The map of Emer found in the Emer boxed set lists Emer around 3900 miles E-W and 3050 miles N-S (excluding the Komaren cluster). The map found in Emer I seems to reflect that size. Except that the size of Emer according to the global map is around 4600 miles E-W and 3630 miles N-S.
The ratio between the two is around 0.83 (0.85 for the map in Emer I).
The ratio between the Jaiman map and the global map is around 0.63.

To muddle things a bit more, I checked the Govon map in Star Crown Empire and the scale was even more off : the map of SCE puts the continent at around 1300 miles N-S. But the global map puts it around 2250 miles. The ratio is 0.57.

I know what scale I use (the one from the global map). But my question is, what is it with regional modules and the map scales ?

[MisterK]

One added detail : the map at the back of the Xa'ar module indicates that the distance between Getesh on the west coast and the easternmost point of Saralis at the straits between the Karish and the L'Kyran is about 350 miles. On the Jaiman map (in Jaiman LoT and in the Haalkitaine book), it is about 250 miles. The ratio makes the Xa'ar map closer to the global map (though still a bit smaller).

[Majyk]

Nice sleuthing.  Even saying it’s the usual misrepresentation all Mercator maps would be incorrect.
For instance, the AuthaGraph World Map Projection is our most accurate 2D map of Earth.

I think they were all written at different times and nobody thought about a single reference point until much later, heh.
“Nobody will notice!” might have been a catchphrase.

Use your global scale and rewrite whatever results you get into the other books.

[Hurin]

For instance, the AuthaGraph World Map Projection is our most accurate 2D map of Earth.

And even that's not that accurate. Though they seem relatively close in size on that map, Greenland is in fact 2 million square kilometers and Africa is 30 million.

[terefang]

with all that inaccuracy, my wish of a GIS-quality world map have been evaporated

[kmanktelow]

Probably won't help but years ago I was working with the Astronomy program Celestia and got the crazy idea of putting Kulthea in there. Attached is one of the files I was working on - a Mercator projection of the whole of Kulthea. I was then brushing in real satellite data from Earth on the landscape. Never finished it and can't find the original Celestia files - some of the pictures generated using Celestia did appear in the Players Guide.

Actually, not 100% sure that the projection file will be allowed as it's a bit large - up to 60 meg for some of them. So a OneDrive link is provided to the folder.

https://1drv.ms/u/s!AuOfIRuJvq23j5gtVBFgCcboKO6qkg?e=0hR8rJ

[MisterK]

More sleuthing on the global map (SWMA4)...

The map is 49 cm long E-W (roughly a hemisphere if the lore is right). It is 41 cm high, but the pole maps add to that and are 8.3 cm in diameter/ The sum is thus 49.3 cm, which means that the E-W demi-perimeter is almost the same size as the N-S demi-perimeter. Hurrah !

Furthermore, the pole map perimeter is about 26.1 cm, so half-perimeter is 13.05 cm. The cumulative length (longitudinal) of the mapped area on the north side is 15.2 cm, and 13.3 on the south side. Basically, the map as represented is a bit too large in the upper northern latitudes, and almost OK in the lower southern latitudes.

The problem is when we reach the mid-latitudes. Halfway between the equator and the north pole, the cumulated length (longitudinal) of the mapped area is 44.3 cm. At 45° north, it should be about 34.5 cm. This is a significant inflation and the continent sizes reflect that. Coincidentally, the 45th parallel goes right through Jaiman.

It would seem that the continent dimensions, as defined by the global map, would be OK N-S, but not E-W, and the E-W dimension inflation would vary depending on the latitude : OK at the equator (because that's the basic hypothesis), not that bad at the sub-polar map end around 75° north, but wrong anywhere between those, and probably the wrongest in the mid-latitudes (the 45° inflation is almost 30%).

Which means that the "more or less not too wrong" dimensions of Jaiman would be about 1800 miles from north to south (global map size), but only about 1700 miles from east to west. Basically, you take the Jaiman map and squeeze it a bit laterally (and squeeze it a bit less on the north end than on the south end).

Emer, on the other hand, would be significantly smaller on its northern shores, but exactly the same  size at the equator, which is just south of the Grotto Path and the southern shores of Uj and Onar.

I dearly wish I could use an image morphing program to alter the global map and get sizes that would match a spherical planet better...

[on a tangent : I rummaged through the old Atlases and Space Master, and I got that the distance between Kulthea and its sun is slightly larger than the earth-sun distance, and, if Kulthea is indeed Ceril VII in Space Master, the sun is listed as a G3 star while our sun is a G2 - so Kulthea's sun is also slightly cooler. It would make sense, then, that Kulthea is slightly cooler than our earth on the average]