[R] coordinates from locator function in POSIXct format

jim holtman jholtman at gmail.com
Fri Jul 29 19:02:58 CEST 2011

I keep the following function handy so that I can change the numeric
value from POSIXct back to POSIXct; I tend to keep the numeric in
matrices since it allows faster operations in some cases.  This just
puts the appropriate classes on the object; quicker than using
as.POSIXct(z, origin="1970-01-01")

 unix2POSIXct <- function (time) structure(time, class = c("POSIXt", "POSIXct"))

> z <- 1285038419
> as.POSIXct(z, origin="1970-01-01")
[1] "2010-09-21 04:06:59 EDT"
> unix2POSIXct(z)
[1] "2010-09-20 23:06:59 EDT"

On Fri, Jul 29, 2011 at 9:40 AM,
<cristabel.duran at waldbau.uni-freiburg.de> wrote:
> Dear R-list,
> I have a plot with y-axis corresponding to wind measurments
> and x-axis with date-time information.
> When I want to identify some extrem wind events in the
> wind-curve, I use locator() to get the exact
> date-information, by clicking in the points in graph I´m
> interested in.
> I get in the R console the x and y coordinates.
> The x coordinates are not in a POSIXct format, I guess R is
> returning the x coordinates in a time unit as miliseconds
> or something else.
> Do anyone how to get the x coordinates directly in a
> POSIXct format?
> Thanks in advance!
> Cristabel.
> Cristabel Durán Rangel. PhD Student.
> Institute of Silviculture. Faculty of Forest and
> Environmental Sciences. University of Freiburg.
> Germany
> Telf: +49 (761) 203 8604 (ofc)
> „Man lernt die Physiognomie einer Landschaft desto besser
> kennen, je genauer man die einzelnen Züge auffaßt, sie
> untereinander vergleicht und so auf dem Wege der Analysis
> den Quellen der Genüsse nachgeht, die uns das große
> Naturgemälde bietet.“
>                                Alexander von Humboldt, 1799
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Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?

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