Dielan9999 said:
I think 4 in each cardinal direction will do, and perhaps in the other 4 directions (NE, NW, SE, SW) but at different distances from the spawn!
Putting the Herogates in the four diagonal directions
before the cardinal ones would be wiser, and I'll tell you why... in diagrams!
Wherever we place the Herogates, we want them equidistant from Sanctum, each in its own "quadrant". Now, the poorly drawn Figure 1 shows what you propsed (sorry for my lack of MSPaint skillz :S ): Sanctum (S) in the middle of the map, with herogates at N, E, S, and W, about half-way between Sanctum and the border. If you want, then, to get to a place somewhere on the map, you'd look at Figure 1. (in your mind) and see which triangular "quadrant" your destination is in. It'd be a little confusing to be able to decide which quadrant it's in (and therefore which gate to use), not too rough, but moreover, look at how far the borders are from the Herogates at some parts, especially close to the corners of the map. If your destination is a corner of the map and you choose one of the two close Herogates, your distance, the maximum possible travel distance to any point on the map, would be sqrt(2500^2+1250^2) = 3535 metres.
Now! If the gates are placed NE, NW, SE, and SW (centre of each quadrant (though a little closer to the border would actually be more appropriate) as in Figure 2), the problem of deciding which quadrant the destination is in is as simple as
looking at the polarity of the coordinates. If x is negative (north of sanctum) and z is positive (west of sanctum) then the destination is in the north-west quadrant of the map, and you would use the NW Herogate (if walking from Sanctum would be further). Furthermore, the farthest possible distance one would have to walk would again be from a Herogate to a corner of the map, which in each case is sqrt(1250^2+1250^2) = 1767 meters, half of the distance than if the Herogates were placed in the cardinal directions.
Your idea of having two sets of four Herogates is still better than what I drew up in Figure 1, but the discussion is to determine if we can get by with just four Herogates, which we can if we follow the outline in Figure 2.
For these reasons, it is wiser to place the Herogates diagonally from Sanctum.