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### [Idea] a real Earth (if possible)

Posted: Tue Aug 14, 2018 02:05
to check what is needed to accept, to change ...

I mean the Earth as a round ball, in the center of the possible map

- max measures −30912 to 30927 in the axis, mean nearby 61840 nodes place,
and the earth is
- the real radius is 6.371 until 6.378 kilometer, or 12.750 km in diameter
- the highest up hill on land is near 9 km up
- the atmosphere is not so important, rain clouds are 0.5 km and up ... a thunderstorm cloud top from 10 - 15 km

61.000 Nodes place for a ball with 12.750 km full size.
So a factor of up-sizing of 4.5 could be taken, mean 57.375 nodes used, left 3625, is too less for a atmosphere ? ... also difficult to calculate all time

Take a factor of 4:
12.750 km * 4 = 51.000 Nodes used on central axis,
10.000 Nodes left, or in real (/2/4) 1.250 km air space free on the shortest parts from surface to border ... .
seams to much not used space

factor 5 would crash the 8 sizes to the border ... ?
5 * 12.750 = 63.750 is more than the max of: 61840 Nodes (miss 1910, or (/2/5) 191 km at 8 positions)
(if getting these points to the oceans, and let them be smaller ... hmmm)
191 km is already magma area ...

So as using max of space, but keep it more easy to calculate a factor ... (max 61840 Nodes) for 12.750 km
* 4 = 51.000 nodes, rest 10.840 nodes or 1.355 km over smallest area or
* 4.5 = 57.375 nodes, rest 4.465 nodes or 496 km left for air or
* 4.75 = 60.563 nodes, rest 1.277 nodes or 124 km left around ...
* 4.8 = 61.200 nodes, rest 640 nodes or 67 km, hmm
* 4.825 = 61.519 nodes, left 321 nodes what is 33 km space around ...
* 4.85 = 61,838 nodes, left 2 nodes ... just enough to pass flying there ...

So even how to get that basic "ball" with the continental shelf ... a surfave is ok, the inside of earth not needed full, but could let a open triangle to show the inside also ...

### Re: [Idea] a real Earth (if possible) 2

Posted: Tue Aug 14, 2018 02:06
What would be possible to see at this factors ?

sure continents, covered with woods, leaves, dessert ...

So if 1 km is near 5 nodes,
object above 200 meter or square could have a own node.

* Most Landmarks like lakes would be seen (200 to 200 meter lake is one node water)
** Rivers only the big ones near ocean

* so only every 200 meter real climb of landmass, there would be a grow up of one node then.
** Mount Everest with 8848 meter, /200 = would be 43 nodes high(er than the base).
** the Mariana Trench - 11.034 meter / is 53 nodes deep(er than the base)
- - - -(that would be the minimum base to produce the balls surface, and have to build up the rest ?)

* Towns
** Manhattan has about 16+ to 3 km, so the nodes for it are just 77 to 15 nodes, that would not be enough for a memorization building (the central park is 19 to 3 nodes green)
- so Towns further 200 meter diameter may just be a area of gray "concrete" - better then gray sign with the name of it ...

### Re: [Idea] a real Earth (if possible) 3

Posted: Tue Aug 14, 2018 02:06
What have to be changed at some mods to do it ?

* water should not follow gravity, just a water block should stay there, or
** we just do colored blocks simulate the coastlines, and build also the real surface of oceans
* if using lava for the core area, also no gravity, have to stay where it is ...
- - - (gravity effect to water, lava and sand)

* gravity itself is no problem for the people at first, that is to fly around that globe

As the sun in the game has its direction, the earth would not stand straight north up, it has to be sidewards 90 degrees (the real North-pole has to look to the northern end of map) so that one side of the planet gets a real sunrise (east) and down (west) haha

What Items are needed ?
* water
* (lava)
* rock / stone
* dessert stone (see on google earth the Australian area most red rock)
* leaves for the forests
* dirt with grass for the grasslands/farmlands (so here how to change direction of the dirts grass )
* snow / ice
* sand (gobi, sahara) - should also not fall then

### Re: [Idea] a real Earth (if possible) 2

Posted: Thu Aug 16, 2018 17:49
Festus1965 wrote:So if 1 km is near 5 nodes,
object above 200 meter or square could have a own node.
And this ends the case ;)

I'd put it this way: let's assume that you're going to create and publish ordinary 2d atlas of the Earth in scale 1mm in map -> 200m of terrain. In other words the scale would be 1:200000. The amount of data necessary to collect to prepare such huge publication is only available for the largest government institutions and certainly not accessible for free on the net. And the sheer volume of such a gargantuan book, which couldn't certainly be published in other way than in a series of tens of huge tomes would make it an unrealistic and purely absurd endeavour for any crazy enough to conceive such a ridiculous idea publisher .

So it is impossible to make such a detailed atlas in Minetest (and I don't know of any other similar thing on Internet except, of course, Google Maps). Of course this is true only if you mean making a voxel globe which would reflect the real terrain precisely enough to call it a map.

Nevertheless your idea is interesting as another kind of map generators creating erthlike planets for exploration.

### Re: [Idea] a real Earth (if possible)

Posted: Fri Aug 17, 2018 16:10
https://github.com/Jeija/spheretest <- Kinda what youre searching.

### Re: [Idea] a real Earth (if possible)

Posted: Tue Oct 23, 2018 23:04
LMD wrote:https://github.com/Jeija/spheretest <- Kinda what youre searching.
Spheretest isn't adapted to the geometry of a real planet. It is topologically a torus, which would make the North and South poles coincide. But it can look nice for regions far from the poles.

Have a look at Lentebriesje's Earth map converted for Minetest by sofar: viewtopic.php?f=12&t=19564
also you might be interested in my mod geo-mapgen: viewtopic.php?f=9&t=19387
Both of them are planispheres.

Paramat is the only one to have explored rounded-shape map generation, although it is not designed to generate real terrain. You can find it here: viewtopic.php?f=11&t=7887. But due to the constant Z-ward gravity of Minetest, these maps are not actually playable unless you stand at the north pole.

### Re: [Idea] a real Earth (if possible)

Posted: Thu Jun 06, 2019 21:24
I wrote:Spheretest isn't adapted to the geometry of a real planet. It is topologically a torus, which would make the North and South poles coincide.
I must contradict myself on that point, I found this map projection that would make possible to represent a real planet on Spheretest, except than each place would exist twice. It represents the Earth as a doubly-periodic 2:1 rectangle so that adding a reversed copy of the rectangle on the top of itself would make a square that could be tesselated.

Sadly I have no idea how to generate such a map with geographical data. The projection libs that I know doesn't support this weird projection, and the maths behind it aren't trivial.

### Re: [Idea] a real Earth (if possible)

Posted: Fri Jun 07, 2019 01:47
With Earth being 40000km in diameter, a scaled version could occupy -20000 0 -20000 to 20000 0 20000, which would give 40km on the edge. This scales down by a factor of 1000. Everest would be 8 nodes high.

A simple math calculation indeed. But does this work?

I would argue, no. In my Opensim days, a region of space occupied 256 meters on the edge. Later this region size increased to a possible 8192 meters (8km) on the edge. Regions were connected into a grid, and one could freely go from region to region. Later still, the developers were able to create a way for the various grids to further connect to one another, thus enabling rather large spaces. The roadblock, other than walled gardens, was that at some point, address space became an issue, or simply generating meaningful space became too cumbersome. Nothing in Opensim was automatic, like biomes.

You can try using lib_materials / lib_ecology for the flora. I've tried to mimic real world nature systems in those mods. They should be light enough to be server friendly as well.

### Re: [Idea] a real Earth (if possible)

Posted: Fri Jun 07, 2019 07:28
ShadMOrdre wrote:With Earth being 40000km in diameter, a scaled version could occupy -20000 0 -20000 to 20000 0 20000, which would give 40km on the edge. This scales down by a factor of 1000. Everest would be 8 nodes high.

A simple math calculation indeed. But does this work?
The first idea on this topic was to generate a real, spherical Earth, potentially using Spheretest. But the problem with it is that Spheretest wraps the world cyclically in both directions, which would mean that, on a standard Mercator map, if you reach the north pole, you get teleported to the south.

As for generating a simple planisphere with geographical data, it's something I've already been working on quite much, see geo-mapgen.

### Re: [Idea] a real Earth (if possible)

Posted: Sat Jun 08, 2019 09:21
Gael de Sailly wrote:
ShadMOrdre wrote:With Earth being 40000km in diameter, a scaled version could occupy -20000 0 -20000 to 20000 0 20000, which would give 40km on the edge. This scales down by a factor of 1000. Everest would be 8 nodes high.

A simple math calculation indeed. But does this work?
The first idea on this topic was to generate a real, spherical Earth, potentially using Spheretest. But the problem with it is that Spheretest wraps the world cyclically in both directions, which would mean that, on a standard Mercator map, if you reach the north pole, you get teleported to the south.

As for generating a simple planisphere with geographical data, it's something I've already been working on quite much, see geo-mapgen.
You might be also interested in this one: https://www.seedofandromeda.com/blogs