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Trajectory subsetting

Source: R/subsetTrajectories.R
subsetTrajectories.Rd

Subsets data structures for trajectory analysis

Usage

subsetTrajectories(
  x,
  site_selection = NULL,
  subtrajectory_selection = NULL,
  survey_selection = NULL
)

Arguments

x

An object of class trajectories (or its children subclasses fd.trajectories or cycles)

site_selection

A character vector indicating the subset of entity (site) trajectories to be selected (if NULL, all sites are included).

subtrajectory_selection

A character vector indicating the subset of cycles or fixed date trajectories to be selected (only used when x is of class fd.trajectories or cycles).

survey_selection

An integer vector indicating the subset of surveys to be included (if NULL, all surveys are included).

Value

An object (list) of class trajectories (or its children subclasses fd.trajectories or cycles), depending on the input.

Details

When using function subsetTrajectories on cycles or fixed-date trajectories then the parameter site_selection applies to sites (hence allows selecting multiple cycles or fixed-date trajectories). Specific cycles or fixed-date trajectories can be selected using trajectory_selection.

See also

defineTrajectories, trajectoryCyclical

Examples

#Description of entities (sites) and surveys
entities <- c("1","1","1","2","2","2")
surveys <- c(1,2,3,1,2,3)
  
#Raw data table
xy<-matrix(0, nrow=6, ncol=2)
xy[2,2]<-1
xy[3,2]<-2
xy[4:6,1] <- 0.5
xy[4:6,2] <- xy[1:3,2]
xy[6,1]<-1

d <- dist(xy)

# Defines trajectories
x <- defineTrajectories(d, entities, surveys)
x
#> $d
#>          1        2        3        4        5
#> 2 1.000000                                    
#> 3 2.000000 1.000000                           
#> 4 0.500000 1.118034 2.061553                  
#> 5 1.118034 0.500000 1.118034 1.000000         
#> 6 2.236068 1.414214 1.000000 2.061553 1.118034
#> 
#> $metadata
#>   sites surveys times
#> 1     1       1     1
#> 2     1       2     2
#> 3     1       3     3
#> 4     2       1     1
#> 5     2       2     2
#> 6     2       3     3
#> 
#> attr(,"class")
#> [1] "trajectories" "list"        

# Extracts (subset) second trajectory
x_2 <- subsetTrajectories(x, "2")
x_2
#> $d
#>          1        2
#> 2 1.000000         
#> 3 2.061553 1.118034
#> 
#> $metadata
#>   sites surveys times
#> 1     2       1     1
#> 2     2       2     2
#> 3     2       3     3
#> 
#> attr(,"class")
#> [1] "trajectories" "list"