R/senGetPathRow.R

In RGISTools: Handling Multiplatform Satellite Images

#' Return the pathrow of a tile from Sentinel-2 images
#'
#' \code{senGetTile} reads the official name of a Sentinel-2 image and returns 
#' the tile's path and row number, in "\code{TTTSSS}" format (Sentinel naming
#' convention).
#' 
#' Find more details about the Sentinel tiling system 
#' \href{https://sentinel.esa.int/web/sentinel/missions/sentinel-2/news/-/asset_publisher/Ac0d/content/sentinel-2-level-1c-product-tiling-grid-released}{here}.
#'
#' @param str the full path(s) or official name(s) of the Sentinel-2 images from
#' which the tile's path and row numbers are retrieved.
#'
#' @return a string with the path and row in "\code{TTTSSS}" format.
#'
#' @examples
#' # getting path and row numbers from a couple of Sentinel-2 images
#' files.sen <- c("S2A_MSIL1C_20170102T111442_N0204_R137_T30TWN_20170102T111441.SAFE",
#'                "S2A_OPER_PRD_MSIL1C_PDMC_20160308T090616_R094_V20160305T110109_20160305T110109")
#' pr.sen <- senGetTile(files.sen)
#' print(pr.sen)
#'
senGetTile<-function(str){
  name.first<-gsub(".SAFE","",basename(str))
  # Sentinel-2 images
  if(substr(name.first,1,2)[1]=="S2"){
    sizes<-sapply(name.first,nchar)
    sTime<-c()
    for(s in 1:length(sizes)){
      if(sizes[s]!=78){#new name convention
        sTime<-c(sTime,gsub(".*\\s*([A-Za-z]{1}\\d{2}[A-Za-z]{3}).*", "\\1", names(sizes[s])))
      }else{#old name convention
        sTime<-c(sTime,"")
      }
    }
  }else{
    stop("Introduced image path is not a supported Sentinel image name.")
  }
  
  return(sTime)
}


#' Return the relative orbit of the Sentinel-2 satellite 
#'
#' \code{senGetOrbit} reads the official name of a Sentinel image and returns 
#' relative orbit, in "\code{NXXXX_RYYY}" or "\code{RYYY}" format (Sentinel
#' namig convention).
#' 
#' Get information about the relative orbits
#' \href{https://sentinel.esa.int/web/sentinel/missions/sentinel-2/satellite-description/orbit}{here}.
#'
#' 
#' @param str the full path(s) or official name(s) of the Sentinel images from
#' which the orbits are retrieved.
#'
#' @return an string with the relative orbit of the image in "\code{NXXXX_RYYY}"
#' or "\code{RYYY}" format, depending on the version of name convention.
#'
#' @examples
#' #example of getting date from Sentinel2 image name
#' files.sen <- c("S2A_MSIL1C_20170102T111442_N0204_R137_T30TWN_20170102T111441.SAFE",
#'                "S2A_OPER_PRD_MSIL1C_PDMC_20160308T090616_R094_V20160305T110109_20160305T110109")
#' tile.sen <- senGetOrbit(files.sen)
#' print(tile.sen)
#'
senGetOrbit<-function(str){
  name.first<-gsub(".SAFE","",basename(str))

  # Sentinel-2 images
  if(substr(name.first,1,2)[1]=="S2"){
    sizes<-sapply(name.first,nchar)
    sTime<-c()
    for(s in 1:length(sizes)){
      if(sizes[s]!=78){#new name convention
        sTime<-c(sTime,gsub(".*\\s*(N\\d{4}_R\\d{3}).*", "\\1", names(sizes[s])))
      }else{#old name convention
        sTime<-c(sTime,gsub(".*?\\s*(R\\d{3}).*", "\\1", names(sizes[s])))
      }
    }
  }else{
    stop("Introduced image path is not supported Sentinel image name")
  }
  
  return(sTime)
}