View standard Movebank IMU data column sets

Movebank has several standard ways to store data for each IMU sensor. These functions show the recognized columns for each sensor that can be extracted from a move2 or data.frame by default.

• movebank_acc_colsets() — standard column sets for as_acc().

• movebank_mag_colsets() — standard column sets for as_mag().

• movebank_gyro_colsets() — standard column sets for as_gyro().

To extract IMU data from columns whose names don't correspond to Movebank's conventions, provide a custom set of IMU columns with imu_colset().

Usage

movebank_acc_colsets()

movebank_mag_colsets()

movebank_gyro_colsets()

Value

A named list of imu_colset objects.

Details

IMU data are stored in two ways:

• Expanded-format columns store each IMU sample (possibly for multiple axes) in its own row.

• Compact-format columns store a burst of IMU samples as a space-delimited string. This string must be segmented into axis-specific values using an associated column that indicates the axes present in the burst. A further column provides the sampling frequency of the burst. All three of these columns must be present to form a valid compact-format column set.

Alternate column name separators

Some column names may differ depending on how the data were downloaded. The Movebank API (e.g. move2::movebank_download_study()) provides columns with _ separators, while manually downloaded data uses : and - separators and occasionally includes additional prefixes. For full compatibility, the active_*_colsets() functions recognize these alternate spellings as additional column sets even though movebank_*_colsets() lists only the standard API names.

For future compatibility, consider converting data with the manually-downloaded column names to use _ separators. To use a custom column set, provide the names explicitly with imu_colset().

See also

active_acc_colsets(), active_mag_colsets(), active_gyro_colsets() to identify column sets present in a tabular data source.

Examples

movebank_acc_colsets()
#> $eobs
#> <imu_colset> [
#>   bursts = "eobs_accelerations_raw",
#>   axes = "eobs_acceleration_axes",
#>   frequency = "eobs_acceleration_sampling_frequency_per_axis"
#> ]
#> 
#> $raw
#> <imu_colset> [
#>   bursts = "accelerations_raw",
#>   axes = "acceleration_axes",
#>   frequency = "acceleration_sampling_frequency_per_axis"
#> ]
#> 
#> $acc
#> <imu_colset> [
#>   bursts = "accelerations",
#>   axes = "acceleration_axes",
#>   frequency = "acceleration_sampling_frequency_per_axis"
#> ]
#> 
#> $xyz
#> <imu_colset> [
#>   X = "acceleration_x",
#>   Y = "acceleration_y",
#>   Z = "acceleration_z"
#> ]
#> 
#> $raw_xyz
#> <imu_colset> [
#>   X = "acceleration_raw_x",
#>   Y = "acceleration_raw_y",
#>   Z = "acceleration_raw_z"
#> ]
#> 

movebank_mag_colsets()
#> $raw
#> <imu_colset> [
#>   bursts = "magnetic_fields_raw",
#>   axes = "magnetic_field_axes",
#>   frequency = "magnetic_field_sampling_frequency_per_axis"
#> ]
#> 
#> $xyz
#> <imu_colset> [
#>   X = "magnetic_field_x",
#>   Y = "magnetic_field_y",
#>   Z = "magnetic_field_z"
#> ]
#> 
#> $raw_xyz
#> <imu_colset> [
#>   X = "magnetic_field_raw_x",
#>   Y = "magnetic_field_raw_y",
#>   Z = "magnetic_field_raw_z"
#> ]
#> 

movebank_gyro_colsets()
#> $raw
#> <imu_colset> [
#>   bursts = "angular_velocities_raw",
#>   axes = "gyroscope_axes",
#>   frequency = "gyroscope_sampling_frequency_per_axis"
#> ]
#> 
#> $xyz
#> <imu_colset> [
#>   X = "angular_velocity_x",
#>   Y = "angular_velocity_y",
#>   Z = "angular_velocity_z"
#> ]
#>