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So, what I am doing is creating a heatmap for x and y coordinates. But I would like to do this for every 30 minute interval. For example the first heatmap will be created using the data from "00:00:00" to "00:30:00", then the next from "00:01:00" to "00:31:00".

What I need help with is writing a for loop that can extract these rows from a larger database and then spit out the heatmap for each bracket of data. I have been told that zoo::rollapply could be useful in the process but am not sure how it works.

The database has three columns x, y, and indiv.times. x and y are the coordinate systems and indiv.times is a character variable which contains the times in the format "13:04:46" for example.

for (i in ???) {
  kde <- kde2d(x, y)
  plot_ly(z = kde$z, type = "heatmap")
}

This is the code to create the heatmap so I really just need a way to extract the 30 minute intervals.

Any help would be greatly appreciated.

Here is a sample of the database:

structure(list(x = c(224.7666, 223.3886, 131.7025, 345.333), 
    y = c(60.7657, 85.73872, 77.35342, 26.24607), indiv.times = Sys.time() +
    cumsum(60*sample(20, size = 10, replace = TRUE)), class = "data.frame", row.names = c(NA, -4L)))
Ekatef
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Seamus O'Leary
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1 Answers1

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So if anyone else is interested, I created an index i that has all the times from "00:00:00" all the way to "24:00:00". Than inside the for loop you just need to extract the rows from the data frame where df[time < i + 1800 & time > i,]. Make sure your times are in the time format and not just strings. Then you can perform any adjustments in the for loop using the new extracted data frame.

Seamus O'Leary
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