import_expom_RF: Import .csv, .xls or .xlsx files downloaded from the ExpoM-RF...

In MarloesEeftens/EMFtools: Helpful tools for research on the epidemiology of electromagnetic fields.

Description

Given the pathname of a file downloaded from the ExpoM-RF, this function imports the speficied file into the R environment as a dataframe.

Usage

import_ExpoM_RF(filename,prefix,suffix)

Arguments

filename	The complete pathname (including path, name and extension) to the file you want to import into R.
prefix	(Optional, no default) Sometimes it is handy to import the column names with a prefix (e.g. "EXPOM_") so they are unique within the dataframe if you want to use the time series to compare with another instrument. The result of specifying a prefix is that all columns in the imported dataset (except for PosixTime) are named (e.g. "EXPOM_") EXPOM_dect, EXPOM_2100UL, etc.
suffix	(Optional, no default) Similar to above. The result of specifying a suffix (e.g. "_Vm") is that all columns related to frequency bands show this suffix in their variable name (e.g.) dect_Vm, 2100UL_Vm etc.

Value

The result is an R dataframe of your ExpoM-RF file which is ready to work with and includes the variables:

PosixTime	POSIXct, date and time of each observation.
FM	numeric, Field strength [V/m] in the 87.5–108 MHz band.
TV	numeric, Field strength [V/m] in the 470–790 MHz band.
DL800	numeric, Field strength [V/m] in the 791–821 MHz band.
UL800	numeric, Field strength [V/m] in the 832–862 MHz band.
UL900	numeric, Field strength [V/m] in the 880–915 MHz band.
DL900	numeric, Field strength [V/m] in the 925–960 MHz band.
UL1800	numeric, Field strength [V/m] in the 1710–1785 MHz band.
DL1800	numeric, Field strength [V/m] in the 1805–1880 MHz band.
DECT	numeric, Field strength [V/m] in the 1880–1900 MHz band.
UL2100	numeric, Field strength [V/m] in the 1920–1980 MHz band.
DL2100	numeric, Field strength [V/m] in the 2110–2170 MHz band.
WIFI2G	numeric, Field strength [V/m] in the 2400–2485 MHz band.
UL2600	numeric, Field strength [V/m] in the 2500–2570 MHz band.
DL2600	numeric, Field strength [V/m] in the 2620–2690 MHz band.
WIMAX	numeric, Field strength [V/m] in the 3400–3600 MHz band.
WIFI5G	numeric, Field strength [V/m] in the 5150–5875 MHz band.
TOTAL	numeric, Total field strength [V/m] in all bands above.
id	numeric, ID of the ExpoM-RF sampling device.
latitude	numeric, Latitude in decimal degrees.
longitude	numeric, Longitude in decimal degrees.
speed	numeric, Estimated speed that the device is moving in [km/h].
nr_sats	numeric, Number of satellites available to determine the coordinate.
marker	numeric, Markers counted as the marker button was pressed.
charge	numeric, Percentage charge remaining.
charging	logical, Whether (TRUE) or not (FALSE) the device was charging.
overload	logical, Whether (TRUE) or not (FALSE) the device experienced an overload.

Note

As far as I know, R packages do not support example .xlsx files... The function should work also for them. The example .xlsx file is only available from within SwissTPH. But chances are you have your own anyways! Exported .xlsx files contain field strengths with 16 digits after the decimal point, whereas .csv files only 4 digits after the decimal point. This is false precision in the .xlsx files, since the difference is ±0.00005 V/m, which is just 1/60 of the lowest band's quantification limit (0.003 V/m). We have removed this false precision in the .xlsx import, by rounding all field strenghts to 4 digits. The resulting R files are identical (aside from slighly different rounding methods), no matter if .csv or .xlsx was used to save the original data.

Author(s)

Marloes Eeftens, [e-mail]

Examples

#Write the example .csv to a folder of your choice (please change pathname!):
my_filename1<-"V:/EEH/R_functions/EMFtools/data/expom_example2.csv"
write.table(expom_example2,file=my_filename1,sep="\t",quote=FALSE,row.names=FALSE)
#Import using the import function:
my_expom_file1<-import_expom_RF(filename=my_filename1,prefix="EXPOM_",suffix="_Vm")
str(my_expom_file1)

#Read an .xlsx file into R:
my_filename2<-"V:/EEH/R_functions/EMFtools/data/expom_example3.xlsx"
my_expom_file2<-import_expom_RF(filename=my_filename2,prefix="EXPOM_",suffix="_Vm")

#The files are identical whether imported as .xlsx or .csv:
identical(head(my_expom_file1),head(my_expom_file2))
#Although there are small rounding inconsistencies between the .csv's (rounded in MatLab?) and the .xlsx's, rounded in R:
my_expom_file1$FM[1689]
my_expom_file2$FM[1689]

MarloesEeftens/EMFtools documentation built on May 10, 2019, 5:16 a.m.