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Hi Steven,

If you haven't set the timezone for your data correctly, that can be an
issue -- the default is UTC, which is EST + 4 or 5 hours (depending on
daylight savings)

Grabbing the tide data from the "rtide" package looks like it has
geographical data, which sets an appropriate time zone:
```
tz(tidepredict$Date.Time[1]) # returns "EST"
```

while the default for your counts is UTC:
```
tz(counts$Date.Time[1]) # returns "UTC"
```

When you convert your read-in csv data using `mdy_hm()`, you should be able
to specify the time zone, which I think will solve your issue.

Best,
--
Hao Ye
[log in to unmask]


On Fri, Dec 7, 2018 at 11:20 AM Longmire,Steven <[log in to unmask]>
wrote:

> Hi everyone,
>
>
> I have a (large) dataset of tide level predictions that are in an interval
> of every five minutes, and I have a (large) dataset of bird observations
> with a date.time stamp. I am trying to see if there is a correlation with
> tide level and bird counts.
>
>
> Issue: whenever I try to merge the two data frames by date.time using
> 'left_join', it LOOKS like it works, and the date.times seem to line up,
> but when comparing the tide levels to the original data set's tide levels
> at the same time stamp, it is very off (shifted by about 5 hours or so). I
> think it has something to do with the date.times, because when I converted
> both to numeric to compare, two of the seemingly identical times gave
> different numerical values and tide levels.
>
>
> Any help is appreciated!
>
>
> Steven
>
>
>
> This list strives to be beginner friendly. However, we still ask that you
> PLEASE do read the posting guide
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwIFaQ&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=QWxQId63qB2iSP1ggUL7kQsdfEWUTu6qCGEw8Xuo91A&m=b4WRmmOMr6Amcof0s09ZHRQQyh5533wA1RwRlKBoPpA&s=88TuYjpQkAGakJI1fJCAU3cU7QvI4gXDQNa9nI0R8Zw&e=
> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwMFAw&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=SEmRVMqAFbH_Cx3K2dozZfH2QG2rALCjx8XkDKdS6dE&m=DqYWew3vW5xBPNPiJ5Ww1lCNJLO8oG5YUsVr0l3snaM&s=NbQoOjNTdakpuBLmjQqG8iy3vQVw02I0nX13aE4inDc&e=>
> and provide commented, minimal, self-contained, reproducible code.

This list strives to be beginner friendly.  However, we still ask that you
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.