LocST_UTC: Calculate UTC from Local Solar Time

In MLezamaValdes/LocST:

Description

calculate UTC from Local Solar Time, as provided e.g. in MODIS viewtime rasters

Usage

LocST_UTC(LocST, utc, lon = NULL)

Arguments

LocST	Local solar time vector in mm:hh format or as a viewtime raster in decimal format or decimal format only
utc	UTC day that was provided e.g. via filename or the corresponding UTC day (converted to UTC time from the local time zone the local solar time was reported for), format = '%Y-%m-%d' or as POSIXlt date
lon	required only if no raster is used for LocST, to provide as decimal point numeric

Value

data frame with lon and lat, as well as decimal format local solar time ("LocST"), hour format local solar time "LocST_h",UTC date calculated from LocST "utc_from_LocST", the original UTC input provided ("orgUTC") and a time difference between provided and calculated UTC times in case a POSIXlt format UTC date was provided (available e.g. in case of MODIS L2 / swath data)

Author(s)

Maite Lezama Valdes

Examples

library(raster)
#using MODIS L2 product's viewtime raster
vtr_s <-raster(system.file("extdata", "vtr_s.tif", package="LocST"))
utcdate <- strptime("2018-01-19 13:50", format='%Y-%m-%d %H:%M', tz="UTC") # info derived from MOD11_L2 filename A2018019.1350
LocST_UTC(LocST=vtr_s, utc=utcdate)

#using MODIS viewtime raster from daily products, where no UTC capture time is available
vtr_s <- load(vt_raster)
LocST_UTC(LocST=vtr_s, utc="2018-01-19")

#using LocST without raster, lon input is required
LocST_UTC(LocST="23:36", lon=137.8628, utc="2018-01-19")
LocST_UTC(LocST=23.6, lon=137.8628, utc="2018-01-19")

#using multiple LocST inputs for the same longitude
LocST_UTC(LocST=c(23.0, 22.1), lon=137.8628, utc="2018-01-19")

MLezamaValdes/LocST documentation built on June 6, 2019, 7:40 p.m.