nether portal linking help please

[Davykinz]

So this is just a question for minecraft in general.

I have a nether portal in my town. i recently found The End, a few hundred blocks away, more than 256 blocks for sure. set up a nether portal there, planned on creating a mine cart system in the nether from wherever that portal brought me to the village portal in the nether. simple. but when i went thru the portal i made in the end, it connected me to the first portal i had in the nether which was originaly connected to the portal in my town. and now i cant get back to the end through the nether. i thought the portals only link with the another portal if its like 256 blocks or less away?
help please. i still want to do the railcart system

thanks in advance!

 

[Zelgar]

Build the portals yourself at the right locations (over world divided by 8) and you will link up correctly. You can ignore height to an extent, but it will cause problems if you have a lot of tightly packed destinations.

 

[SevenMass]

The easiest way to set up a working nether portal system is to do it manually, as suggested.
You can't even count on the generated portals to be at the right equivalent coordinates, because the algorithm tries to find a "nice" place for the portal that is neither in the air nor inside solid netherrack.

To explain the mechanics: The algorithm searches for an existing portal in the target dimension within a 256 by 256 block cube with the equivalent coordinates in the middle. You could also say it searches in a 128 block radius, except that that it's search area isn't a circle.

So to generate a new portal in the nether, the equivalent coordinates need to be more than 128 blocks away from an existing portal in the nether. This means 1024 blocks in the overworld.
The other way around, to generate a new portal in the overworld, you need to create a new portal in the nether only 16 blocks away. (assuming the existing portal is at the right equivalent coordinates)
This means that if you want to guarantee a new portal in the nether to be generated, you need to create a new portal in the overworld 1040 blocks away from any existing portals.

If you set up your portal net manually, the overworld portals can be as close as 8 blocks away from each other.

Of course, if you play with mod's, there is little reason to mess about with vanilla portals. Just use a Mystcraft intra-linking book or two, and you don't need to go to the nether at all.