I'm looking to read block data from one Minecraft world and write the data into certain places in another.

I have a Minecraft world, let's say "TemplateWorld", and a 2D list of Point objects. I'm developing an application that should use the x and y values of these Points as x and z reference coordinates from which to read constant-sized areas of blocks from the TemplateWorld. It should then write these blocks into another Minecraft world at constant y coordinates, with x & z coordinates determined based on each Point's indices in the 2D list.

The issue is that, while I've found a decent amount of information online regarding Minecraft world formats, I haven't found what I really need: more of a breakdown by hex address of where/what everything is.

In reality, I could have the TemplateWorld actually be a .schematic file rather than a world; I just need to be able to read the bytes of the file, know that the actual block data starts always at a certain address (or after a certain instance of FF, etc.), and how it's stored. Once I know that, it's easy as pie to just read the bytes and store them in memory.

Then, I need to know how to write block data to a "new" world. I'll just have a flatland world in a folder, and generate a copy of it for pasting into at the start of the operation. I just don't know how to store the data into this world.