cut.trip | R Documentation |

Split trip events within a single object into exact time boundaries, adding interpolated coordinates as required.

```
## S3 method for class 'trip'
cut(x, breaks, ...)
```

`x` |
A trip object. |

`breaks` |
A character string such as the |

`...` |
Unused arguments. |

Motion between boundaries is assumed linear and extra coordinates are added at the cut points.

This function was completely rewritten in version 1.1-20.

list of S4 trip objects, each with aligned boundaries in time based on cutting the input into intervals

A list of trip objects, named by the time boundary in which they lie.

Michael D. Sumner and Sebastian Luque

See also `tripGrid`

.

```
set.seed(66)
d <- data.frame(x=1:100, y=rnorm(100, 1, 10),
tms= as.POSIXct(as.character(Sys.time()), tz = "GMT") + c(seq(10, 1000, length=50),
seq(100, 1500, length=50)), id=gl(2, 50))
sp::coordinates(d) <- ~x+y
tr <- trip(d, c("tms", "id"))
cut(tr, "200 sec")
bound.dates <- seq(min(tr$tms) - 1, max(tr$tms) + 1, length=5)
trip.list <- cut(tr, bound.dates)
bb <- sp::bbox(tr)
cn <- c(20, 8)
g <- sp::GridTopology(bb[, 1], apply(bb, 1, diff) / (cn - 1), cn)
tg <- tripGrid(tr, grid=g)
tg <- sp::as.image.SpatialGridDataFrame(tg)
tg$x <- tg$x - diff(tg$x[1:2]) / 2
tg$y <- tg$y - diff(tg$y[1:2]) / 2
op <- par(mfcol=c(4, 1))
for (i in 1:length(trip.list)) {
plot(sp::coordinates(tr), pch=16, cex=0.7)
title(names(trip.list)[i], cex.main=0.9)
lines(trip.list[[i]])
abline(h=tg$y, v=tg$x, col="grey")
image(tripGrid(trip.list[[i]], grid=g), interpolate=FALSE,
col=c("white", grey(seq(0.2, 0.7, length=256))),add=TRUE)
abline(h=tg$y, v=tg$x, col="grey")
lines(trip.list[[i]])
points(trip.list[[i]], pch=16, cex=0.7)
}
par(op)
print("you may need to resize the window to see the grid data")
cn <- c(200, 80)
g <- sp::GridTopology(bb[, 1], apply(bb, 1, diff) / (cn - 1), cn)
tg <- tripGrid(tr, grid=g)
tg <- sp::as.image.SpatialGridDataFrame(tg)
tg$x <- tg$x - diff(tg$x[1:2]) / 2
tg$y <- tg$y - diff(tg$y[1:2]) / 2
op <- par(mfcol=c(4, 1))
for (i in 1:length(trip.list)) {
plot(sp::coordinates(tr), pch=16, cex=0.7)
title(names(trip.list)[i], cex.main=0.9)
image(tripGrid(trip.list[[i]], grid=g, method="density", sigma=1),
interpolate=FALSE,
col=c("white", grey(seq(0.2, 0.7, length=256))),
add=TRUE)
lines(trip.list[[i]])
points(trip.list[[i]], pch=16, cex=0.7)
}
par(op)
print("you may need to resize the window to see the grid data")
data("walrus818", package = "trip")
library(lubridate)
walrus_list <- cut(walrus818, seq(floor_date(min(walrus818$DataDT), "month"),
ceiling_date(max(walrus818$DataDT), "month"), by = "1 month"))
g <- rasterize(walrus818) * NA_real_
stk <- raster::stack(lapply(walrus_list, rasterize, grid = g))
st <- raster::aggregate(stk, fact = 4, fun = sum, na.rm = TRUE)
st[!st > 0] <- NA_real_
plot(st, col = oc.colors(52))
```

trip documentation built on July 9, 2023, 7:29 p.m.

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