## Create a data.frame of 10-minute intervals stored as POSIXct
## You can convert most times to POSIXct using as.POSIXct if they are not already that format
lizard <- data.frame(time=seq(from=as.POSIXct('2015-01-01 00:00:00'), to=as.POSIXct('2015-01-02 00:00:00'), by=10*60))

## Randomly eliminate rows with probability of 15% that a given row is eliminated to create gaps
lizard$keep = runif(nrow(lizard))
lizard <- lizard[lizard$keep <= .85, c('time'), drop=FALSE] ## drop arg used to kepe it a dataframe

## Random lat / lon data:
lizard$Lat = runif(nrow(lizard)) ## runif is random uniform
lizard$Lon = runif(nrow(lizard))

## We initialize to NA; the distance variable for row i will represent the distance between row i-1 and i;
## row 1 will not have a meaningful value
lizard$distance <- NA
lizard$distance[2:nrow(lizard)] <- distanceTrack(lizard$Lat, lizard$Lon)

lizard$isContiguous <- TRUE ## initialize a variable to determine if the data is at 10-min interval
lizard$isContiguous[2:nrow(lizard)] <- (as.numeric(lizard$time[2:nrow(lizard)] - lizard$time[1:nrow(lizard) - 1]) == 10)
lizard <- lizard[lizard$isContiguous, ] ## filter