This function reads Actigraph GT3X and ActiSleep accelerometer files.
gt3xAccFile(file, path, fileid, tz = "Europe/London",
sparse = FALSE, fault = 32767)
These functions return an object of two class
es: accfile
and additional device-specific class (i.e., gt3x
).
An object of class accfile
is a list containing the following components:
A data.frame
object with accelerometer values in columns y
, x
, z
, and steps
(if present), and coded error for each accelerometer data column. See errorChk
for error codes. If sparse = TRUE
, all variables of the data frame df
are returned as vectors of a matrix in sparse format (see as.matrix.csr
for details).
A data.frame
object with file identifier (fileid
), device serial number (serial
), number of recorded measurements (nobs
), epoch (epoch
), accelerometer mode (mode
), start date and time (ts_start
), time zone (tz
), battery voltage (voltage
), download date and time (ts_dl
).
A list
object with file identifier (fileid
), summary tables of error codes for each accelerometer data column, error code for date (date
), and logical flag for odd number of measurements (odd_number
) (see details).
file name including file extension.
path to file
.
label for file identifier.
a character string specifying the timezone to be used for the conversion (see strptime
).
logical flag: should data be stored in sparse format?
numerical value that indicates voltage signal saturation.
Marco Geraci
Raw accelerometer data are processed according to the device data format. See file 'gt3x_sample.dat' in directory '\inst\extdata' of this package.
Actigraph (Pensacola, Florida).
Geraci M, Rich C, Sera F, Cortina-Borja M, Griffiths LJ, and Dezateux C (2012). Technical report on accelerometry data processing in the Millennium Cohort Study. London, UK: University College London. Available at https://discovery.ucl.ac.uk/1361699
readAccDir
data(gt3x_sample)
class(gt3x_sample)
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