[R] representing points in 3D space with trajectories over time

[Umut Toprak]

Thank you Greg

I will likely go with a list of data frames as each data frame will
represent independent entities and as the syntax will probably be
better that way.

I did find it puzzling that multidimensional data frame or the ability
to hold a vector in a cell of a data frame was not added in a 3rd
party package if not the core. I will find a way to work around this
though.

Best,
Umut

On Thu, Oct 17, 2013 at 7:46 PM, Greg Snow <538280 at gmail.com> wrote:
> If all your data is numeric then you can use an array instead of a data
> frame and arrays can easily be 3, 4, or higher dimensional.  Or you can use
> a data frame with a column each for x, y, z, and time; with possible other
> columns representing groups or other attributes, essentially a 3 dimensional
> data frame with the 3rd dimension being stacked rather than projecting out.
>
>
> On Thu, Oct 17, 2013 at 6:59 AM, Umut Toprak <umut.toprak at unige.ch> wrote:
>>
>> Dear all,
>>
>> I have a problem where I must represent points with XYZ coordinates
>> changing over time. I will do a number of operations on this data such as
>> calculating the YZ-projection distance of the points to the origin over
>> time, the frequency spectrum of the X-T data etc. I am trying to find a
>> good way of representing this data with an appropriate data structure.
>>
>> It appears like higher-dimensional data frames are not allowed and I do
>> not
>> know if I should use a list of data frames or if there is a better
>> solution, possibly as part of an external package.
>>
>> Thank you for your time
>> Umut Toprak
>>
>>         [[alternative HTML version deleted]]
>>
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>
>
>
> --
> Gregory (Greg) L. Snow Ph.D.
> 538280 at gmail.com