Visualization of time series data includes sending to the data source a request for visualizing sensor data within a canvas having a width of w pixels and covering a visualization time range, each pixel of the canvas being representative of a time duration Iopt, receiving consecutive sets of tuples that each covers a time interval having the time duration It, performing a M4 aggregation comprising generating, from the received tuples, a set of consecutive w groups, each group of the w groups comprising tuples covering a time interval having the time duration Iopt, and determining for each group of the w groups a set of aggregates, and displaying the w sets of aggregates on the canvas of the browser window as a chart, wherein each one of the sets of aggregates is displayed in one of pixel columns of the canvas.