Identify rows containing IMU data

These functions return a logical vector flagging the rows of an input move2 or data.frame that contain sample data for the specified sensor. These are the rows that will be used to build IMU bursts when calling as_acc(), as_mag(), or as_gyro().

Usage

acc_sample_rows(x, colset = NULL)

mag_sample_rows(x, colset = NULL)

gyro_sample_rows(x, colset = NULL)

Arguments

x

A move2 or data.frame.

colset

An imu_colset object or list of imu_colset objects specifying the columns to check for IMU data. By default, all active colsets detected in x are considered (see active_acc_colsets()).

Value

A logical vector the same length as nrow(x). TRUE values indicate rows where IMU data is present under at least one active colset.

Details

If x has data in more than one active IMU column set, *_sample_rows() will return TRUE. However, these rows cannot be parsed by as_acc(), as_mag(), etc. as they contain duplicated IMU data. To ensure that *_sample_rows() only considers certain column sets, use the colset argument.

If no active colset is detected (e.g. data with only GPS records), *_sample_rows() returns FALSE for all rows.

For expanded-format data (where multiple rows compose a single burst) all rows that contain IMU data are flagged TRUE. However, the output of as_*() will not necessarily return bursts at each of these locations, as multiple of these rows will be combined into a single burst.

See also

as_acc(), as_mag(), as_gyro() to extract IMU data from a move2 or data.frame.

active_acc_colsets(), active_mag_colsets(), active_gyro_colsets() to inspect which colsets are detected in x.

Examples

alb <- albatrosses()

head(acc_sample_rows(alb))
#> [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE

# Filter to rows with acc data without building bursts
nrow(alb[acc_sample_rows(alb), ])
#> [1] 45