BTCUSDSHORTS and BTCUSDLONGS are like datasets provided by Bitfinex exchange. They record the number of margined for longs and shorts and they are measured in BTC (in case using BTCUSD ). Margin is Like any loan, the borrower may pay interest while the loan is outstanding, and must eventually pay the loan back.
Red Area: More short margin than long margin. Green Area: More long margin than short margin.
Note: Can only be used with cryptocurrencies that have such dataset within Bitfinex exchange like BTCUSD , ETHUSD , XRPUSD and a few more.