Question

I am wanting to use core plot but before I work on implementing it, I am wondering how it performs with a large number of data points. Some of the data we want to display on a line graph has around 5000 data points.

Can core plot show all of this data on screen without having to scroll to see more data? Will it load this many points fairly quickly? Does core plot cache larger graphs like this?

Any comments about this would be great.

Answer 1

Can core plot show all of this data on screen without having to scroll to see more data?

Sure, the scale of your plot space and axes is independent of the number of data points.

Will it load this many points fairly quickly?

It depends on what format you’re starting with (Core Plot supports several ways of getting data), the device you’re using, and how you define “fairly quickly”. My gut feeling is that loading the data won’t be your bottleneck no matter what format you use–drawing 5000 points will. You’ll probably have to try it to see if it will meet your needs.

Does core plot cache larger graphs like this?

It caches the data in an efficient format and there are methods to add and remove data points without reloading everything. It does not cache the bitmap explicitly. Core Plot uses Core Animation to handle all of the graphical elements, so it takes advantage of the caching and optimizations built into CA.