[robinofloxley]

It's not actually that hard to make a flat map of the Earth from scratch with a bit of programming know how and the internet.

Your projection does not reconcile with know shipping times/distances, known travel times/distances, known flight paths, know flight times/distances outlined in several posts:

I'm not for one moment suggesting it does reconcile with anything in the real world. The original question asked if there was any practical way to actually make a map given gps, the internet etc. What I've presented is a way to do exactly that - to produce an actual map from scratch with some (essentially gps based) data from the internet and a bit of programming. I'm not claiming anything about reality here, just saying how you (i.e. anyone) can go about making their own map.

The only (arbitrary) choice I made here was how to project the data onto a flat surface. I just chose an AE projection. No particular reason other than that's a common projection used on this forum.

[jimster]

You can't do it by asking the software, it displays a mercator projection but gives you the correct distance. You have to use a ruler or string.

Look at Alaska on one of these maps. Look at continental USA, is it 4.7 times the size of Alaska, Mexico is slightly larger than Alaska in sq miles.

I went to the bing map and measured the width of the US as 12 inches, bing says it is 2700 miles. I then measured the width of Alaska from Canadian border to Nome on the west coast at 6 inches. Bing says it is 775.

Why does bing not tell me numbers that have a 2:1 ratio as my measurement says it should be?

You can do this yourself.

Here is either the truth, or very incompetent airline people:

http://www.flyalaska.com/alaskafacts.html

This is not the relative size shown on your mercator projections, because they make things bigger than they are towards the poles.

You can make a computer map that is visually distorted yet reports accurate distances.

What you can't do is make a world map on a flat sheet of paper and measure all distances accurately with a constant scale.

[Balls Dingo]

2. Regardless there are accurate interactive maps which represent the earth as a flat plane which is the entire point.

Those maps are not accurate which is the entire point. Even the example you suggested, freemaptools.com, uses Google Maps which is based on a Mercator projection. It may not be immediately obvious to you but the cities at the top of the map near Stockholm are more spread out than the cities at the bottom of the map near Cairo, ie. their relative distances are incorrect. If you used the same tool I did, even the line between Stockholm and Cairo is slightly curved which indicates distortion.

An example - take a basketball and slice off the top. Now lay the slice flat. You actually can't - the rubber will keep popping up. You'll either have to use some force and stretch it around the edges, or maybe take a pen knife and cut some small slits. You might get something approaching a flat shape but it won't be very accurate. Now draw Australia to scale on that basketball, draw some dots for all the major cities, and cut it out with a pen knife. You'll have the same problem, the rubber will pop up slightly. You'll be able to flatten it out with a little force but that will distort the distances, especially around the edges of the country. There is no flat shape you can make with that rubber where the relative distances between the cities/dots are accurate. You cannot represent Australia on a 2D plane.

[jimster]

Let me make this perfectly clear. What I mean by accurate is all distances everywhere. Any difference in any distance is distorted, and yes, you can project a spherical surface onto a plane, but you can not preserve all distances accurately. Gauss's theorem, mathematically provable. That is why the scale on the map changes with latitude.

You can't do it. There will never be a flat map of earth that has the same scale everywhere and accurate distances everywhere. That can only be done on a globe.

Please show me the map with the same scale everywhere that is flat and has accurate distances everywhere. I will admit that I was wrong, and I am a stupid idiot, and tell everyone that you are a genius.

[birdkage]

https://en.wikipedia.org/wiki/AuthaGraph_projection

[Balls Dingo]

From the Wiki page, "the projection does not qualify as equal-area because the method does not control area at infinitesimal scales or even within those regions".

[jimster]

What happens when I sail east from New York on your map? Many people have sailed west from New Yrok and not run into the edge. Is your map a cylinder? If it is, we only have to tuck the ends in and we have a ball. If it is not, why can people sail east from NY and get to Europe?

[iamcpc]

Those maps are not accurate which is the entire point. Even the example you suggested, freemaptools.com, uses Google Maps which is based on a Mercator projection. It may not be immediately obvious to you but the cities at the top of the map near Stockholm are more spread out than the cities at the bottom of the map near Cairo, ie. their relative distances are incorrect. If you used the same tool I did, even the line between Stockholm and Cairo is slightly curved which indicates distortion.

They are accurate because the scale of the map changes. The map is interactive. It's been demonstrated many times in this thread that the interactive maps have a sliding scale.

What happens when I sail east from New York on your map? Many people have sailed west from New Yrok and not run into the edge. Is your map a cylinder? If it is, we only have to tuck the ends in and we have a ball. If it is not, why can people sail east from NY and get to Europe?

If you are asking about the flat circle map I don't know. That map fails to reconcile with reality in terms of known and measured flight/travel/shipping/driving times and distances.

In the other map which represents the map as a flat plane if you sail east from New York you reach either Europe or Africa depending on your heading. You can't sail west from New York because west of New York is the united states.

[ChrisTP]

Iamcpc, the map is visually distorted, the scales scale up or down for you based on the actual length which is based on a globe  earth but the flat map is still visibly stretched at the top. We all know the scales change as you look higher or lower... That is to be expected on a flat projection of a globe earth and not to be expected on a flat earth.

[Balls Dingo]

They are accurate because the scale of the map changes. The map is interactive. It's been demonstrated many times in this thread that the interactive maps have a sliding scale.

Of course the scale changes but that doesn't fix the problem. Do you understand that if you do the experiments you suggested, zoom to Alaska so it's filling most of the mapquest window and zoom to Mexico so it's filling most of the mapquest window, that shape that you see for Alaska and Mexico is not their actual shape despite the scale in the bottom corner changing? Because there is no 2D representation of those states/countries that is not distorted. You have to stretch it or squash or distort it in some way to make a 2D representation. And the bigger the area you fill the screen with, the greater the distortion. While it's true that if you zoom right in to the highest level, the distortion becomes insignificant for practical purposes, that does not make it an accurate map.

Edit: Just to clear this up once and for all, I've used Mapquest and put in four Australian cities (Broome, Cairns, Perth, and Sydney) and then taken a screenshot. Distance between Broome and Cairns on the screenshot is 536.54 pixels (using the measure tool in Photoshop), in freemaptools, it's 2497.396kms. Distance between Perth and Sydney on the screenshot is 806.68 pixels, in freemaptools, it's 3290.287kms. So the former is 4.6546 km per pixel, the latter is 4.0788 km per pixel. In other words, km per pixel for Broome and Cairns is 14.17% greater than km per pixel for Perth and Sydney. I've also included a screenshot of the shortest distance between those points on freemaptools. It should be obvious that the bottom line is slightly more curved than the top. This is also another way of visualising the distortion on the map. Regardless, if it was possible to have a 2D representation of Australia, it should be possible for the software to make both of those straight lines and they would represent the distances accurately. But it's not. Also, if this was the case, pilots could also throw away their great circle mapping tools for domestic flights within Australia because they could use this amazing, accurate 2D map. But they can't.

Feel free to check my results.

[jimster]

I want to see the FE map where I can't sail into the edge. The polar projection/ice wall explanation is not available to a flat rectangular map. Any flat rectangular map has to explain what is up with the edges. The earth, to a sailor, has no edge. If flat map, must explain edge.

Do you have explanation for edges?