The integrated nature of Spreadsheets and Fusion Tables as data sources make the coding of Charts with these external data sources for the Visualization API quite straightforward.
In Spreadsheets, two preparation steps must be addressed in order to use a Spreadsheet as a data source with the Visualization API. The first is to identify the URL location of the Spreadsheet file for the API code. The second step is to set appropriate access to the data held in the Spreadsheet file.
The primary method of access for a Spreadsheet behaving as a data source is through a JavaScript-based URL query. The query itself is constructed with the Google Query Language (described in more detail later in this chapter). If the URL request does not include a query, all data source columns and rows are returned in their default order. To query a Spreadsheet also requires that the Spreadsheet file and the API application security settings are configured appropriately...