We have the sample data of US States: Number of serious accidents reported for every state in US.

We have this data in three categories: Lowest reported number for a month, Average reported accidents in a year and Highest number reported in a month, as showed in below sample data.

We want to draw a US Map and visualize this data such that, when we hover mouse over a state, it should show this data for that particular state.

AZ: 13 41 57

CA: 41 60 81

NY: 6 35 54 and so on.

• First , we will need to create a US map.

  1. You can either create a map from scratch using sources like - Stately.
  2. Get a already created map from freehtml5maps or use this Javascript

• Add your map to the main javascript used for visualization

  For Example, (script src="uStates.js")(/script) (!-- creates uStates. --)

• Create Div tag to hold tooltip and create SVG to hold you map.

  For Example,

  (div id="tooltip")(/div)
  (svg width="960" height="600" id="statesvg")(/svg)

• Create Tooltip function to create html content string in tooltip div.

  This tooltip function will return a table and this table will be shown whenever we hover mouse over the state Table should be something like this ( As shown in the first figure) : Arizona Low 13 Average 41 High 57

• Draw states on id (#statesvg in our example ) with data and tooltip function.

  For example, uStates.draw("#statesvg", sampleData, tooltipFunc);

  Final output will be something like this: ( Hovered the mouse over California )

1. D3.js Examples and Documentations.
2. NPashaP GitHub
3. Stately
4. FreeHTML5Maps