I'm making a bound map that would require more than 255 locations. So I plan to use Burrow Detection. The thing is, I don't know how locations pick what units to center. I only remember it was from the bottom-left when I read the wiki a long time ago (which is as of now broken). I forgot if the x-axis was the first priority or y-axis was the first priority. I looked at a bound map that used burrow detection but I just got too confused.

Can somebody explain a little more? Thanks.

As far as I recall the X-axis is the first priority (from left to right). If units share the same X coordinate SC centers location on the unit with the lowest ID.

You can easily make a fast test map, which will take you less than 10 minutes.

I thought if it shared the same x-coordinate it would go with the highest (furthest down) y-coordinate

Nope =x In a 3x3 mobile grid, it removes the units in this order (1 being first).

3 4 7
2 6 8
1 5 9

In situations where they share the same X coordinate, it removes the most recently created ones first.

Post has been edited 2 time(s), last time on Oct 12 2010, 12:03 pm by DevliN. Reason: Mineral abuse.

This is a common misconception, because Staredit and its derivatives distribute unit IDs from left to right and then from bottom to top.
And in mobile grids units get created in an counter clockwise spiral, starting below the center unit:
7 6 5
8 1 4
9 2 3

So units with highest number are created last and get the highest ID and these a coincidentally the bottom most numbers for the left row, but as Azrael correctly explained this doesn't work in the 2nd row anymore.

So it's the highest ID that decides, which is most of the time the last created unit.
Keep in mind that ScmDraft hands out IDs in the order you preplace them on your map.

The first unit placed on the map is ID 0. The second unit placed on the map is ID 1699. The third is ID 1698. If a unit shares the same x coordinate, triggers will affect the unit which comes first in the unitnode table (ie the lowest ID). If ID 0 is the first devourer, that means the grid would look like this when removing:
1694 1695 1696
1693 0000 1697
1692 1699 1698

3 5 7
2 4 8
1 6 9

Normally ID 0 is taken up by something that can't die, or won't ever die, but it can get replaced, and is the only exception to the rule I have stated.

There is a good possibility that I am mistaken, however. Instead it could be "If a unit shares the same x coordinate, triggers will affect the unit which has been moved last". If you create 9 devourers at the beginning of the game with no units on the map, then remove them one by one, and it follows the same pattern as Azrael.Wrath has posted, then my first rule is incorrect, and the second rule is probably correct. A way to test this out is to jumble the grid with different IDs. I can't test this out.

However, most of this is moot, since if ID 0 is a permanent structure (which it usually is) the grid works the same for both theories I mentioned.

Okay, so to nail it down, it's:

1st Priority: X-Axis Left to Right
2nd Priority: Unit Index # Greatest To Least

BTW, does anyone know when the wiki might be fixed so that annoying topics like this one never needed to exist?

No, no, Least to Greatest.

Also - the old wiki is still technically working... you just can't access it by the old links any more.

http://www.staredit.net/wiki.php?article=Grid_systems

I just jumbled a bunch of preplaced units, it removed the ones with higher indexes first.

Post has been edited 2 time(s), last time on Oct 12 2010, 12:02 pm by DevliN. Reason: Mineral abuse.

That's because they were placed last.

I just confirmed: it's not based on Index, but how "new" the unit is to that location. Anything you notice with index is an unintentional side effect. It will remove the last unit to have moved to the vertical line.

Also, if you create 9 off the bat, placement ID 0 (the first unit) is removed last because it was placed first.

Ohh, so if you create them somewhere else and then move them to the grid out-of-order, it will remove the most recently moved ones first regardless of index?

Post has been edited 2 time(s), last time on Oct 12 2010, 12:02 pm by DevliN. Reason: Mineral abuse.

correct. If you make 9 units at the start, ID 0 will still be taken away 6th, since it was created first in the column. If you then remove and replace it, or move it away, then back again, it will be first in the column.

Thanks for making the distinction It would certainly make a difference in some situations.

Post has been edited 2 time(s), last time on Oct 12 2010, 12:01 pm by DevliN. Reason: Mineral abuse.

I find this thread very fruitful.

PLOP

What happens if you create the units outside of the location, then center the location on the units?
Theoretically all units have entered the location at the same time...

I believe it's technically not even locations but the "last unit moved/created", however this needs confirmation.
Yeah I'm a lazy butt

Sorry, it's not a "location" but the column.

Oh and the wiki probably won't be fixed, but you can certainly migrate it to the wiki that works.