Plotting large dataset as graph in android -

i need plot daily prices graph in android application. 30 day graph, fetching 30 data points server , plotting it.

for 3(90 data points), 6(180 data points), 12(360 datapoints) month graph, worried increase data download.

what standard options reduce amount of data being transferred? there way can generate 1 data point n days , send them on wire?

are these images? why not generate images server-side, , ship out prebuilt images? can have application ask images on ajax-y call.