Comment by Theodores | Hacker News Reader

Comment by Theodores | Hacker News Reader

What surprises me with visualisation is that you soon find yourself on your own when it comes to making a 'simple' graph. This takes you out in to a whole world of coding that nobody else will ever re-use.

The examples out there will not do for your data and even if you wonder 'am I using the wrong chart for this?' you can find that you are not.

Recently I needed to do a stacked bar chart with different things in each stack. Imagine column 1 - fruit - with that broken down by apples/bananas/oranges and column 2 - vegetables - with that broken down by tomatoes/potatoes/carrots.

The other problem area was colouring the chart. I generated colours in the hsl colour space so that where something was on the chart determined colour and how much of it there was determined saturation/lightness. Some people get offended by eXcel style hard colours so I could not just use random clashing colours and call it a day.

Beautiful visualisations are hard, even with the best graph tools out there I expect some inevitable situation of being an edge case and having to find solutions the hard way. The goal being so that nobody even notices the hard work put in. Only if the graph is ultra intuitive and simple is it going to work with some audiences. Simplicity is hard.

Experimentation when it comes to visualization is a pretty inherent task. Whenever, and I mean literally every time, I start creating a graph, I end up opening at least 5-7 SO tabs, matplotlib, and seaborn docs, etc.

It is just that visualizations are not a solved thing yet.

I'm finding this to be pretty accurate for python viz, but I gotta say, when I was working in R, I got to the point where I could make most graphs without looking at the docs.

While you still need some experimentation to get a plot right, following the grammar of graphics approach can make it quick and methodical. For any plot, I just need to answer a few questions:

* What kind of plot do I want? Bar chart? Scatter plot? Boxplot? Pick the geom based on this.

* What column goes on each axis? Do I need to transform the axis? For e.g., is log scale better?

* Do I split data by some other column? Use different colors/fill, shapes, or facets.

* Do I need any annotations to point out interesting parts of the plot?

GGPlot and Plotnine are joy to work with once you grok the ideas of tidy data and grammar of graphics. Since the API is consistent, experimentation can be quick:

* That scatter plot looks to busy? Change the geom to a boxplot.

* Want to see if an attribute has any predictive power? Assign it to any unused aesthetic.

Seaborn can provide some higher-level functions compared to plotnine/ggplot like pair-plot. But as you said, you need to lookup seaborn's documentation all the time to work with it.

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