Terraria – How does the distribution of ores & chests change with world size

In small worlds, resources are closer together.

In large worlds, resources are farther apart.

According to the Terraria wiki page on World Size,

It also seems that in larger worlds, resources are much farther apart from each other in comparison to the smaller ones. This means that in smaller worlds, resources are much easier to locate and mine

This can be seen by using MoreTerra to display the whole map. Taking same-scale slices of each world size reveals the sparser dispersions of rare resources in the larger maps.

For a numerical argument, you could count the number of rare resources on n small worlds, n medium worlds and n large worlds. Then divide each count by the respective world dimenions and average the numbers. This method will give the average density of resources on each map size. The greater n is, the more accurately average resource density is estimated.

For example, below are three same-scale slices of each world size. Note, this is only one sample, so the total counts do not accurately represent the average resource density of each map size.

Small World

^{4300 x 1200 blocks}

• ^{Altar - 9}
• ^{Chest - 3}
• ^{Heart Stone - 4}
• ^{Shadow Orb - 5}
• ^{Amethyst - 16}
• ^{Diamond - 3}
• ^{Emerald - 9}
• ^{Ruby - 4}
• ^{Sapphire - 12}
• ^{Topaz - 16}
• ^{Total - 81}

Medium World

^{6300 x 1800 blocks}

• ^{Altar - 6}
• ^{Chest - 3}
• ^{Heart Stone - 2}
• ^{Shadow Orb - 7}
• ^{Amethyst - 5}
• ^{Diamond - 0}
• ^{Emerald - 1}
• ^{Ruby - 1}
• ^{Sapphire - 2}
• ^{Topaz - 5}
• ^{Total - 32}

Large World

^{8400 x 2400 blocks}

• ^{Altar - 2}
• ^{Chest - 0}
• ^{Heart Stone - 3}
• ^{Shadow Orb - 9}
• ^{Amethyst - 2}
• ^{Diamond - 1}
• ^{Emerald - 1}
• ^{Ruby - 1}
• ^{Sapphire - 4}
• ^{Topaz - 2}
• ^{Total - 25}

Symbol legend

Another way to find the exact dispersion ratio is to look at the code.

In response to people asking about an open source version of Terraria, Redigit says,

This will probably happen eventually, but the decision to not obfuscate Terraria was made for a reason

So until the open source code is released, somebody could dig through the decompiled code and find the variables that control the base resource density of each map size.