Most finance websites show quotes or charts for various financial markets. Where is this data freely available and how can we download it, wrangle it into a useable format, and visualize it ourselves?

A quote for a financial instrument like a stock, currency, or commodity is a snapshot in time reflecting the sum of individual trades happening on the market for this instrument. Data points like price or trading volume are collected periodically to form a historical time series. If we chart this time series, we can visualize the activity of individual instruments, or the market as a whole with an index, and gain a quick overview, and perhaps some insights into the data.

Below is a who-trusts-whom network of people who trade using Bitcoin on a platform called Bitcoin OTC. Since Bitcoin users are anonymous, there is a need to maintain a record of users' reputation to prevent transactions with fraudulent and risky users. Members of Bitcoin OTC rate other members in a scale of -10 (total distrust) to +10 (total trust) in steps of 1.

Let's see if we can produce some meaningful insights by visualizing a snapshot of the network.

Dataset statistics¶

• Nodes 5,881
• Edges 35,592
• Range of edge weight -10 to +10
• Percentage of positive edges 89%

Sampling¶

One month sample is used with a broad range of ratings.

This notebook explores visualizing historical price data for Bitcoin. A colorized candlestick chart helps visualize daily price trends and larger time frame price trends together: https://en.wikipedia.org/wiki/Candlestick_chart

Fetching Historical Price Data¶

• Use GDAX Exchange API: https://docs.gdax.com/#get-historic-rates
• Parse data and coerse into Pandas DataFrame

Candlestick Chart¶

Use matplotlib and mpl finance library for candlestick support: https://github.com/matplotlib/mpl_finance

Chart shows:

• Bitcoin prices organized by day (in UTC)
• X-axis is Date
• Y-axis is Price at Open, High, Low, and Close of the day

Interpretation¶

• Color:
  • Green candlesticks are "bullish" trend days (increased price)
  • Red candlesticks are "bearish" trend days (decreased price)
• Body: Difference between open and close, day's trend strengh
• Shadows: Day's price range, high above open/close, low below open/close
more ...