R/pixel_history.R

In ARPASMR/myCubeR: Customization of the R-package "CubeR" (Author Mattia Rossi, mattia.rossi@eurac.edu) to access to 'ARPA LOMBARDIA Rasdaman database' via WCS and WCPS queries

#' @title Pixel History
#' @description Returns a pixel history of one or multiple bands from one coverage.
#' @param coverage name of the coverage [character]
#' @param coord_sys coordinate system [character]
#' @param bands coverage bands to calculate and visualize pixel history [character]
#' @param coords coordinates of the location of interest in c(Lat,Lon)[character]
#' @param date date range in format (Ymd) [character]
#' @param desc_url Web Coverage Service (WCS) DescribeCoverage url [character].
#' This URL can be built with the *createWCS_URLs* function
#' @param query_url Web Coverage Service (WCS) for processing the query [character].
#' This URL can be built with the *createWCS_URLs* function
#' @param plot Should the data be plotted [boolean].
#' @import httr
#' @importFrom magrittr "%>%"
#' @importFrom stringr str_replace_all str_split
#' @importFrom urltools url_encode
#' @importFrom grDevices rainbow
#' @export

pixel_history<- function(coverage, coord_sys, bands, coords, date = NULL,
                         desc_url=NULL,query_url=NULL,plot=F){
  
  
  if(is.null(desc_url)) desc_url<-createWCS_URLs(type="Meta")
  if(is.null(query_url)) query_url<-createWCS_URLs(type="Query")
  
  times<-coverage_get_timestamps(coverage=coverage)
  
  if(is.null(date)){
    
    #times <- as.Date(times)
    
    start_date_mod <- times[1]
    end_date_mod <- times[length(times)]
    
  } else {
    
    start_date_mod = date[1]
    end_date_mod = date[2]
    
    times <- times[times >= start_date_mod & times <= end_date_mod]
    
  }
  
  bands_len <- length(bands)
  
  if(bands_len == 0) stop("No Bands Found")
  
  responses = list()
  max_res = list()
  
  
  
  query <-str_c('for c in ( ',coverage,' ) return encode(c
                  [',
                coord_sys[2],'(',coords[1],'),',
                coord_sys[3],'(',coords[2],'),',
                coord_sys[1], '("',
                start_date_mod,'":"', times[length(times)],'")],"csv")')
  
  query_encode  <- urltools::url_encode(query)
  request       <- paste(query_url, query_encode, collapse = NULL, sep="")
  
  r             <- GET(request)
  res           <- content(r, "text")
  
  num <- str_replace_all(res,"\\{","") %>%
    str_replace_all(.,"\\}","") %>%
    str_replace_all(.,"\"","") %>%
    str_split(.,",") %>% unlist() %>%
    str_split(.," ") %>% unlist() %>%
    as.numeric()
  
  responses[[1]] = num
  max_res[[1]] = max(num)
  
  
  resp<-do.call(cbind.data.frame,responses)
  resp<-cbind.data.frame(times,resp)
  names(resp)<-c("Date",bands)
  
  times <- strptime(times,'%Y-%m-%dT%H:%M:%S.000Z')
  
  if(plot==T){
    abs_max <- responses %>% unlist %>% as.numeric %>% max
    
    p <- plot(times,responses[[1]], type="o", col = rainbow(1)[1], lwd = 2, xlab="Date", ylab="Single channels", ylim = c(0,abs_max),
              cex.axis = 1.2, cex.lab = 1.2)
    
    if(length(responses) == 1){
      
      p<-legend("topright", inset = .02,legend=c(bands), col = c(rainbow(length(responses))), pch=15)
      
    } else{
      
      for(l in 2:length(responses)) p <- lines(times, responses[[l]], type = "o", col = rainbow(l)[l], lwd = 2)
      p<-legend("topright", inset = .02,legend=c(bands), col = c(rainbow(length(responses))), pch=15)
      
    }
    
  } else return(resp)
  
}