The flat-earth isn't the definitive world map. It's just an idea to help people grasp the concept of a flat-earth. We haven't mapped the world yet.
If you haven't mapped the world yet, then how do you know that the "map" properly conveys the concept of a flat earth?
In this way :
A) The superficial extent or magnitude of the earth from the northern centre to the southern circumference, can only be stated approximately. For this purpose the following evidence will suffice. In laying the Atlantic Cable from the Great Eastern steamship, in 1866, the distance from Valencia, on the south-western coast of Ireland, to Trinity Bay in Newfoundland, was found to be 1665 miles. The. longitude of Valencia is 10° 30´ W.; and of Trinity Bay 53° 30´ W. The difference of longitude between the two places being 43°, and the whole distance round the earth being divided into 360°. Hence if 43° are found to be 1665 nautical, or 1942 statute miles, 360° will be 13,939 nautical, or 16,262 statute miles; then taking the proportion of radius to circumference, we have 2200 nautical, or 2556 statute miles as the actual distance from Valencia, in Ireland, to the polar centre of the earth's surface.
Another and a very beautiful and accurate way of ascertaining the earth's circumference is the following:--
The difference of longitude between Heart's Content Station, Newfoundland, and that at Valencia or, in other words, between the extreme points of the Atlantic) Cable--has been ascertained by Mr. Gould, coast surveyor to the United States Government, to be 2 hours, 51 minutes, 56.5 seconds." 1
The sun passes over the earth and returns to the same point in 24 hours. If in 2 hours, 51 minutes, and 56.5 seconds, it passes from the meridian of the Valencia end of the cable to that of its termination at Heart's Content, a distance of 1942 statute miles, how far will it travel in 24 hours? On making the calculation the answer is, 16,265 statute miles. This result is only three miles greater distance than that obtained by the first process.
Again in the Boston Post, for Oct. 30th, 1856, Lieut. Maury gives the following as the correct distances, in geographical miles, across the Atlantic by the various routes (circle sailing).
If we take the distance (given in the above table) between Liverpool and New York as 3360 statute miles, and calculate as in the last case, we find a nearly similar result, making allowance for the detour round the south or north of Ireland.
"The difference of time between London and New York which the use of the electric cable makes a matter of some consequence, has latterly been ascertained afresh. It is 4 hours, 55 minutes, 18.95 seconds." 1
The results of these several methods are so nearly alike that the distance
16,262 statute miles may safely be taken as the approximate circumference of the earth at the latitude of Valencia.
Let's see what google maps say about the distances between these places:
Tokio (35 degrees N) - Los Angeles (34 degrees N) = 5471 Mi (8804 km)
Los Angeles - New York (40 degrees N) = 2448 Mi (3940 km)
New York - Istanbul (41 degrees N) = 5009 Mi (8062 km)
Istanbul - Tokio = 5556 Mi (8942 km)
All together (full circumference of the Earth at latitude 34-41 N) = 18484 Mi (29748 km)
B) If the distance from Valencia to the Cape of Good Hope, or to Cape Horn, had ever been actually measured, not calculated, the circumference of the earth at these points could, of course, be readily ascertained. We cannot admit as evidence the calculated length of a degree of latitude, because this is an amount connected with the theory of the earth's rotundity; which has been proved to be false. We must therefore take known distances between places far south of Valencia, where latitude and longitude have also been carefully observed. In the Australian Almanack for 1871, page 126 2, the distance from Auckland (New Zealand), to Sydney, is given as 1315 miles, nautical measure, which is equal to 1534 statute miles. At page 118 of the Australian Almanack for 1859, Captain Stokes, H.M.S. Acheron, communicates the latitude of Auckland as 36° 50´ 05″, S., and longitude 174° 50´ 40″, E.; latitude of Sydney, 33° 51´ 45″, S., and longitude 151° 16´ 15″, E. The difference in longitude, or time distance, is 23° 34´ 25″, calculating as in the case of Valencia to Newfoundland, we find that as 23° 34´ 25″ represents 1534 statute miles,
360° will give 23,400 statute miles as the circumference of the earth at the latitude of Sydney, Auckland, and the Cape of Good Hope. Hence the radius or distance from the centre of the north to the above places is, in round numbers, 3720 statute miles. Calculating in the same way, we find that from Sydney to the Cape of Good Hope is fully 8600 statute miles.
The above calculations receive marked corroboration from the practical experience of mariners. The author has many times been told by captains of vessels navigating the southern region, that from Cape Town to Port Jackson in Australia, the distance is not less than 9000 miles; and from Port Jackson to Cape Horn, 9500 miles; but as many are not willing to give credit to such statements, the following quotation will be useful, and will constitute sufficient evidence of the truth of the foregoing calculations:--
"The Great Britain steamer has arrived, having made one of the best voyages homeward that has yet been effected, viz., 86 days; 72 only of which were employed in steaming; and the remaining 14 days being accounted for by detentions. She left Melbourne on January 6th, and arrived in Simon's Bay on February 10th, or 35 days. She then went round to Cape Town, whence she sailed on the 20th of February; and was afterwards detained for four days at St. Michael's and Vigo. The distance she steamed per log was 14,688 miles; which for the 72 days, gives an average of 204 miles a day." If we multiply the average rate of sailing by the thirty-five days occupied in running between Melbourne and St. Simon's Bay (near Cape of Good Hope), we find that the distance is 7140 nautical miles, From Melbourne to Sydney is 6 degrees of longitude further east, or about S40 nautical miles. Hence 7140 added to 340 give 7480 nautical miles, equal to 8726 statute miles; which is 126 miles in excess of the distance given at page 94.
The following extract furnishes additional evidence upon this important point:--
"EXTRAORDINARY VOYAGE.--Every yachtsman (says the Dublin Express), will share in the pride with which, a correspondent relates a brilliant, and, we believe, unexampled exploit which has just been performed by a small yacht of only 25 tons, which is not a stranger to the waters of Dublin Bay. The gallant little craft set out from Liverpool for the antipodes, and arrived safely in Sydney after a splendid run, performing the entire distance, 16,000 miles, in 130 days. Such an achievement affords grounds for reasonable exultation, not more as a proof of the nautical skill of our amateurs, than of their adventurous spirit, which quite casts in the shade the most daring feats of Alpine climbers." A s the distance from Melbourne to Cape of Good Hope is 7140 nautical miles, as shown by the log of the Great Britain, and as the whole distance from Melbourne to Liverpool was 14,688 nautical miles, it follows that, deducting 7140 from 14,688, that the passage from the Cape of Good Hope to Liverpool was 7548 nautical miles. If we take this distance from the 16,000 miles, which the above mentioned yacht sailed to Sydney, we have as the distance between Cape of Good Hope and Sydney, 8452 nautical, or 9860 statute miles.
In a letter from Adelaide which appeared in the Leeds Mercury for April 20th, 1867, speaking of certain commercial difficulties which had existed there, the following incidental passage occurs:--
"Just as our harvest was being concluded, the first news arrived of anticipated dearth of breadstuffs at home. The times. were so hopelessly dull, money was so scarce, and the operation of shipping wheat a distance of 14,000 miles so dangerous, that for a long time the news had no practical effect."
From England to Adelaide is here stated as 14,000 nautical, or 16,333 statute miles; and as the difference of longitude between Adelaide and Sydney is 23 degrees, equal to 1534 statute miles, we find that from England to Sydney the distance is 17,867 statute miles. Taking from this the 7548 nautical, or 8806 statute miles, we have again 9061 statute miles as the distance between the Cape of Good Hope and Sydney.
From the preceding facts it is evident that the circumference of the earth, at the distance of the Cape of Good Hope from the polar centre, is not less in round numbers than 23,400 miles. Should it ever be shown by actual direct measurement to be more than this distance, then the distance from Cape Town to Sydney must be more than 8600 statute miles.
Let's see what google maps say about the distances between these places :
Sydney -- Cape Town = 2445 Mi (3935 km)
TOO, TOO, TOO, TOO FAR OFF FROM REALITY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Sydney -- Terra del Fuego (Argentina) = 5924 Mi (9534 km) -- STILL VERY FAR OFF FROM REALITY
Cape Town - Terra del Fuego = 4216 Mi (6785 km) -- Much, much closer to reality!!!!