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Re: st: Collapsing data to daily data


From   Brigham Whitman <[email protected]>
To   [email protected]
Subject   Re: st: Collapsing data to daily data
Date   Mon, 28 Feb 2011 19:02:43 -0500

Yes, these options worked out for me, thank you.

I am collapsing the data set to prepare it for a cox proportional
hazard model.  Each data point already has a few variables (distance
to cover, distance traveled, snow depth encountered) with measurements
for each point that I can average together for each day before I make
the model.



On Mon, Feb 28, 2011 at 3:29 PM, Austin Nichols <[email protected]> wrote:
> Brigham Whitman <[email protected]>:
> You can generate a date variable (see
> help dates_and_times##converting
> etc.) and then collapse by that date variable; but what is your aim
> there--do you want mean lat/lon?  Or the centroid of all locations?
> Time weighted?  Think about what you want before you blindly collapse.
>
> On Mon, Feb 28, 2011 at 3:21 PM, Brigham Whitman <[email protected]> wrote:
>> Hello,
>>
>> I have time series data where there are multiple data points per
>> individual per day (it is animal GPS movement data).  I want to
>> collapse these data to get one data point per individual per day.
>> Using Stata's collapse command, I only see functions to collapse from
>> daily data to weekly, monthly, annual, etc. data.  Is there a way to
>> collapse from multiple points per day to daily data?  If anybody has
>> done this before, I would appreciate some advice.
>>
>
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