performance improvement in scatter chart

[mohan]

I am using the line chart and the scatter plot chart. The scatter plot chart slows down with large amount of data around 16,000 points (x and y coordinates represented as double floating point numbers).
Some of data points map to the same pixel on in the canvas and I would like to remove these data points from the data array before rendering the chart. Is it possible to get the actual width and height of chart drawing area in pixels, so I can map my floating point array to pixel location on the canvas and eliminate the duplicate points. I would also like to know if I can map my floating point array to a bit map image and overlay the image on the canvas. I have tried this with other charting technologies and it works in improving the performance.

[Sunil Urs]

Mohan,

I just tried scatter plot with 20,000 dataPoints. Though there was a bit of lag while panning, performance was at acceptable levels. Can you please create a jsfiddle out your so that I can have a look. As of now we haven’t exposed width and height of plot area and hence overlaying bitmap might not be possible.

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Sunil

[Anthony]

I’ve noticed that the scatter plot is much slower than a line chart. Also I’ve noticed that markerType square performs much better than markerType circle or triangle. Any reason for this? I’ve been using a dashed line chart instead of a scatter plot because of the huge performance difference with 100,000 points.

[Indranil]

@Anthony,

This is expected because rendering of scatter charts is relatively slower than line charts as it takes more processing.
And the same applies to the markerType as rendering of circle and triangle requires more calculation.

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Indranil Deo
Team CanvasJS