Google Fusion Tables is an excellent data visualization tool to gather, visualize, and share data tables. With Fusion tables one can create charts, maps, network graphs or any other custom layouts. Here is a small writeup about how we did a Heatmap Visualization of Home Insurance Rates of North East United States Using Google Fusion Tables.
We started by creating google fusion table here. We can create a fusion table by selecting the data source like csv, txt, tsv files or google spreadsheets. If your data source is a google spreadsheet you will be asked to select the sheet.
To plot a map after creating the table you have to select the column with location. Google fusion table automatically highlights the columns with location information in them. You can manually tell Google fusion tables to take other columns as a location column by editing the column type to location by doing
Edit >> Change columns
The locations have to be geocoded before they can be plotted on the map. To start geocoding go to File >> Geocode. Here you will be asked to select the location column which is used to geocode. After selecting click on Geocode. It usually takes some time for geocoding to finish depending upon how many locations you have in your sheet. Please note that there is a limitation of 1000 places.
After geocoding, Click on the Heat Map dropdown on the left sidebar to choose the radius, opacity of the heat map.Using the “weight” drop down we can also select the column from which the data will be used to generate heat map.