MODIS (version 1.0.0)

extractDate: Extract Dates from (MODIS) Files

Description

This function helps to extract dates from a vector of files.

Usage

extractDate(files, pos1 = 10, pos2 = 16, asDate = FALSE,
  format = "%Y%j")

Arguments

files

character vector of filenames from which to extract dates.

pos1

integer, start of date string in files.

pos2

integer, end of date string.

asDate

logical. If TRUE, the result is converted to a Date object.

format

character, date format. Used only if asDate = TRUE. Defaults to MODIS date style (i.e., "%Y%j" for year and julian day). See strptime for modifications.

Value

If asDate = FALSE, a character vector; else a Date vector extracted from files.

Examples

# example on HDF files
files <- c("MOD13Q1.A2010209.h18v03.005.2010239071130.hdf",
           "MOD13Q1.A2010225.h18v03.005.2010254043849.hdf")
extractDate(files)
extractDate(files,asDate=TRUE)

# on any other file 
files <- c("Myfile_20010101.XXX","Myfile_20010115.XXX","Myfile_20010204.XXX")
extractDate(files,pos1=8,pos2=15)
extractDate(files,pos1=8,pos2=15,asDate=TRUE,format="\%Y\%m\%d")