58:27
There are a bajillion different charts available in software like excel or numbers or sheets or mathematica or plotly, but I recently discovered that pretty much all plotting apps - as far as I can tell - are missing an incredibly basic type of chart! Consider this video my attempt to convince you it's a scandal these charts are missing, and my attempt to convince software developers to add them into their plotting software. Ok, so suppose you want to compare the climates of London, England; London, Ontario; and London, Kentucky. Here's a table showing the average and
seasonal high and low temperatures for each London. But tables are boring. If you wanted to plot this data by hand, you might imagine using a chart like this to show the range of temperatures and allow you to see at a glance that the climate in London England is less extreme than the other Londons, (which are each similarly variable but with Ontario shifted colder) - a bar chart makes more sense than, say, a point chart since the temperatures in these Londons can by definition be in between the minimum and maximum ones in our table.
The problem is, you can't easily make a chart like this on a computer. You can get close with an area chart, which plots the temperatures correctly, adds nice shading in between them, but also fills the area all the way down (or up) to the X axis, which isn't right. You can get around the filling problem by creating a new table of the differences between the temperatures and plotting that as a stacked area chart. oops - we need to remove the fill from the lowest value - but it still doesn't make sense to use a chart that draws connecting lines in a situation like this where we're talking about discrete geographic locations. You can also get close with a stacked bar chart
(or "stacked column chart" depending on whether you think bars can be both horizontal and vertical or if you think vertical bars have to be called columns.) anyway, a stacked bar-column chart separates out the cities correctly but incorrectly adds the temperatures together - hence, "stacked" - the columns are stacked together, appropriate to the name, but it's not what we want. You can get around the stacking problem by again creating a table of the differences between the temperatures, but then it still fills down to zero even if you want the bars to start at
some other number, and the negative values are a total nightmare" since stacked column charts by default plot things from zero and if you enter a negative number for the first value to try to get it to start below zero, it plots that amount below zero, but then measures the positive numbers up from zero anyway and not from the negative number - this is because stacked column charts are meant for things like keeping inflows and outflows separate, like, you bought 5 cats and sold 2, and you want the total length of bars to represent the total number of transactions (7) and not the final
number of cats (3). The only reasonable way I've found to deal with negative numbers in stacked column charts is just to add a big number to ALL the temperatures so they're not negative anymore, make the chart, then photoshop the y axis labels to remove the big number. Which is ridiculous. What we're actually looking for is something called a "range chart" where you enter the top and bottom values of the range and then the program draws that for you. Specifically, we want a "stacked range bar chart" where you can enter multiple numbers, including negative
numbers, and then draw bars between them. Is that too much to ask? I guess, I guess it is. ps here are a few more examples of data that really would benefit from being visualized with a stacked range bar chart but first, a big thank you to my Patreon supporters who help make these videos possible - please consider supporting MinutePhysics at patreon.com/minutephysics. Now, back to the benefits of stacked range bar charts! Really, any chart where the x axis is a discrete set of things and the y axis is a range that can go below and above zero is a candidate for this
type of chart. Like, if you wanted to plot the range of latitudes of each of the continents, or show when twilight, dusk, and daytime are at a given location. Or compare percentiles for student grades in different classes. Or the local climate: plotting the average daily low and average daily high temperatures for each month along with the average monthly low and high temperatures and the record monthly low and high temperatures across a year gives you a picture of the seasonal variation in temperature for a particular location. Yes, you can do this
with a stacked area chart, but that makes less sense than stacked columns because area implies some sort of continuity when to create the data you are literally binning or averaging by month.
