Indeed, if you have lots of datapoints that define the line, when you switch to bars you will need to draw the same number of bars. The bars usually need more room than the line points, so it is possible that they appear too narrow. Indeed, a possible workaround is to change the chart datasource (or re-create it) so that one bar appears for every 5 (it might be 10 or 20, depending on the overall number) adjacent points from the line. This bar may represent the average value of these points.
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