[Ethereum] n easy, human centric way of viewing local Ethereum blockchain data

Data structures are stored in Merkle Patricia tries (read this and this), usually inside a LevelDB store. The chaindata is exactly that.

I think the structure might slightly depend on the actual node implementation?

Here are two of the trie implementations, could be a good starting point:

• in Go (geth): https://github.com/ethereum/go-ethereum/tree/master/trie
• in Javascript: https://github.com/ethereumjs/merkle-patricia-tree

Once that is understood, you will need to look up the data structures sent over the network, especially blocks, transactions, accounts and storage. Accounts refer to both externally owned and contract accounts, the latter with contract code. Storage refers to contract storage.

Back to the point of data analysis

You might be better off building a traditional NoSQL or SQL database if you want to have quick lookups about any transactions done by an account or contract. What the chaindata is optimised for is validating transactions and maintaining a valid state, and not so for historical lookups.

If i'm not misstaken, this is stated in EIP 155:

If block.number >= FORK_BLKNUM and v = CHAIN_ID * 2 + 35 or v = CHAIN_ID * 2 + 36, then when computing the hash of a transaction for purposes of signing or recovering, instead of hashing only the first six elements (ie. nonce, gasprice, startgas, to, value, data), hash nine elements, with v replaced by CHAIN_ID, r = 0 and s = 0. The currently existing signature scheme using v = 27 and v = 28 remains valid and continues to operate under the same rules as it does now.

So, if chainId = 1, then v becomes 37 or 38 which is the value you are seeing.