Updates to README, and added the log scale note.

README.md

@@ -1,13 +1,36 @@
-**[Click here to see the visualization.](http://todo.com)**
+# cryptographic
+A cryptocurrency visualization. **[Click here to view.](http://todo.com)**
 
-It's an exciting time from cryptocurrency. As of February 2018, there are more than a thousand in existance, with a combined market capitlization of over USD $390 billion.
 
-This is around half the size of *Apple Inc.*, the largest company in the world, valued by markets according to its $375 billion in assets and $230 billion of annual revenues.
+## Introduction
+It's an exciting time for cryptocurrency. As of February 2018, there are more than a thousand currencies in existence, with a combined [market capitalization](https://en.wikipedia.org/wiki/Market_capitalization) of over **USD $390 billion**.
 
-This visualization shows just 25 of these cryptocurrencies. It's a sample which shows all of the major currencies, plus some others of historical or technological significance. 
+For comparison, this is around half the size of *Apple Inc.*, the largest publicly-traded company in the world, valued by markets according to its $375 billion in assets and $230 billion in annual revenues.
 
-# cryptographic - A cryptocurrency visualization
+Just one year ago, this combined crypto market capitalization was less than $19 billion. Two years ago it was less than $8 billion. A lot of apparent wealth has been created in a very short space of time.
 
+The preeminent and original cryptocurrency, Bitcoin, has grown by ~2200% in that two year period. The remaining growth (~2700%) has come from the alternative currencies (altcoins), which now account for around two thirds of the total market.
+
+This visualization shows just 25 of these cryptocurrencies. It's a sample which shows all of the major currencies, plus some others of historical or technological significance. The 25 selected account for over 90% of the total market capitalization, and over 85% of the total trade volume.
+
+The aim of this visualization is to tell a story of the evolution of cryptocurrency. It shows the different directions the technology has gone, and how the various currencies are now valued relative to each other.
+
+Data for this visualization has been sourced from the excellent: [coinmarketcap.com](https://coinmarketcap.com/).
+
+
+## Technology
 This is a *Pie + Radar + Gauge Chart* written in JavaScript with **d3.js** and **SVG**.
 
-This entire visualization is data driven. You can modify `data.csv` and the graphic will update accordingly. The one exception are the section labels which appear on each pie piece; these have been hand-positioned and are drawn from a static overlay file that you can find under `assets/`. 
+This entire visualization is data driven. You can modify `data.csv` and the graphic will update accordingly. The one exception are the section labels which appear on each pie piece; these have been hand-positioned and are drawn from a static overlay file that you can find under `assets/`.
+
+## Rendering
+
+Just serve up the static files in this repository from a web server; then load it with a web browser.
+
+For example:
+
+```bash
+$ npm install -g http-server
+$ http-server .
+# Open a browser to localhost:8080
+```

graphic.js

@@ -755,6 +755,15 @@
             .attr('x', bubbleX)
             .attr('y', y)
             .attr('class', 'key-vol');
+
+        y += 40;
+
+        // Draw the log scale note
+        svg.append('text')
+            .text('Relative metrics use a log scale.')
+            .attr('x', bubbleX)
+            .attr('y', y)
+            .attr('class', 'key-log');
     }
 
     function humaniseNumber(val) {

index.html

@@ -96,6 +96,13 @@
             fill: #333;
         }
 
+         #graphic .key-log {
+            font-size: 12px;
+            text-anchor: middle;
+            alignment-baseline: text-before-edge;
+            fill: #333;
+        }
+
         #graphic .key-cap {
             font-size: 14px;
             font-weight: bold;