EDIT: If anybody understands how the triggers in that map work, can they please explain it to me.
Here's my explanation for the triggers in Minimap-Show-4x3-Z.scm.
I know it's long. Tell me to clarify if something's vague.
Custom score is the counter. Player 8 adds 1 to it every trigger cycle. Ore and gas is just for the benefit of the players (or maybe the mapmaker), to see how much time has elapsed.
Player 6 is the "blank" or "neutral" player, and
Player 4 is the "primer" player. The "Terran Marine" death count is used to give sections of the screen from Player 6 to Player 4 in preparation for the animation. Every time a cannon is given to any player in order to display that player color on the minimap, it was given FROM Player 4, unless it was Player 6 or Player 4, which are also used in animation. This is probably because Player 4 appears as the green floor and walls and makes up most of the movie, and Player 6 is a lot of the walls. Therefore, most of the other players are merely subtractions or cuts into the large blocks of color made up by Players 4 and 6.
MAIN TRIGGER (owned by "All Players", the one with Condition 'Current Player's Custom score is exactly X')
For each second...
1. Set specific Terran Marine Death Count
2. Set List of Death Counts that will display animation. Starts with Zerg Zergling.
Here's what happens in each cycle (each new custom score):1. All cannons are given to Player 6 to "wipe" the screen.
2. The necessary sections of the screen are given to Player 4, according to the proper Terran Marine Death Count. These are the "active sections" -- the ones that will be part of the display. For example, '33554432' for Terran Marine will give the first two columns of cannons (called 'Scan 0') to Player 4 in preparation for the Display.
3. The Display information starts:
a. the first Death Count is checked. For example, '306783379' for Zerg Zergling for Player 1. The first applicable trigger is Force 2's 'Current Player has suffered 268435456 deaths of Zerg Zergling'. This gives one cannon owned by Player 4 to a certain player (in this case, Player 9), updating the minimap display. Since all of Player 4's cannons are currently in the first two columns, it will give one cannon in the first column to Player 9. The applicable Death Count is wiped (exception: see Note below).
b. the next Death Count is checked, and it goes through a similar process as above. This continues until all the remaining Death Counts have been checked for that cycle.
Note: The triggers with Death Counts as conditions are arranged in descending order. The only exception to this is triggers giving cannons to Player 1 always have ranges as conditions (e.g. 'at least 1 and at most 268435455 deaths of zerg zergling'). This accounts for the little red blip that stays there at the top left of the map. Not sure what it's for.
Looking through the triggers, at first it may seem like there are not enough Give actions to account for the large swathes of color that occur in the animation, but it's because the Give actions update faster than the minimap does, so you get multiple Give actions in before the minimap updates.
Of course, the question is how he decided which death counts would apply to which Give operations, but as Joker47 said, he had a program for that. Since most Give operations are probably used many times throughout the movie, most of the operations are recycled.
As for why he fills up each main trigger with 'Modify death counts for player 8: set to 0 for terran marine', I'm not really sure. Maybe they're placeholders. My guess is it had something to do with the generation of the triggers through his own program and don't really have any effect on the behavior of the map.
None.