Combining time-series data with different resolution

I have a number of vectors with different length due to the fact that I have rainfall data (at 1 minute resolution), moisture content (at 15 minute resolution) and climatic data (at 1 hour resolution). All of the vectors have the same start and end time value (datenum format).

I am looking to create a plot matrix and therefore need the vectors to be the same length. Hourly resolution would be ok. Can anybody help??

[Adam]

What do you mean by a plot matrix?

You can plot all three on the same graph despite them being at different resolutions. They don't need to all be in a single matrix for that.