analyse.R

# Usefull library
library(dplyr)
library(zoo)
library(StatsAnalysisTrend)
library(lubridate)
library(trend)


# Sourcing R file
source('processing/format.R', encoding='latin1')


# Compute the time gap by station
get_lacune = function (df_data, df_info) {
    
    # Get all different stations code
    Code = levels(factor(df_info$code))
    
    # Create new vector to stock results for cumulative time gap by station
    tLac = c()
    # Create new vector to stock results for mean time gap by station
    meanLac = c()

    # Get rows where there is no NA
    NoNA = complete.cases(df_data)
    # Get data where there is no NA
    df_data_NoNA = df_data[NoNA,]

    # For every station
    for (code in Code) {
        
        # Get only the data rows for the selected station
        df_data_code = df_data[df_data$code==code,]
        # Get date for the selected station
        Date = df_data_code$Date
        # Get time span for the selection station
        span = as.numeric(Date[length(Date)] - Date[1])
        
        # Get only the data rows with no NA for the selected station
        df_data_NoNA_code = df_data_NoNA[df_data_NoNA$code==code,]
        # Get date for the selected station
        Date_NoNA = df_data_NoNA_code$Date
        
        # Compute the time gap
        lac = as.numeric(diff(Date_NoNA) - 1)

        # Compute the cumulative gap
        lac_sum = sum(lac)
        # Store the cumulative gap rate
        tLac = c(tLac, lac_sum/span)

        # Compute the mean gap
        lac_mean = mean(lac[lac != 0])
        # Store the mean gap
        meanLac = c(meanLac, lac_mean)
        
    }
    
    # Compute the cumulative gap rate in pourcent
    tLac100 = tLac * 100
    
    # Create a tibble
    df_lac = tibble(code=Code, tLac100=tLac100, meanLac=meanLac)
    
    return (df_lac)
}



get_intercept = function (df_Xtrend, df_Xlist, unit2day=365.25) {
    
    df_Xtrend$intercept = NA

    for (g in df_Xlist$info$group) {
        df_data_code = df_Xlist$data[df_Xlist$data$group == g,]
 
        df_Xtrend_code = df_Xtrend[df_Xtrend$group == g,]

        Start = df_Xtrend_code$period_start
        UStart = levels(factor(Start))
        End = df_Xtrend_code$period_end
        UEnd = levels(factor(End))
        
        nPeriod = max(length(UStart), length(UEnd))

        for (i in 1:nPeriod) {

            df_data_code_per = 
                df_data_code[df_data_code$Date >= Start[i] 
                             & df_data_code$Date <= End[i],]

            df_Xtrend_code_per = 
                df_Xtrend_code[df_Xtrend_code$period_start == Start[i] 
                              & df_Xtrend_code$period_end == End[i],]
            
            id = which(df_Xtrend$group == g 
                       & df_Xtrend$period_start == Start[i] 
                       & df_Xtrend$period_end == End[i])

            mu_X = mean(df_data_code_per$Qm3s, na.rm=TRUE)

            mu_t = as.numeric(mean(c(Start[i],
                                     End[i]),
                                   na.rm=TRUE)) / unit2day
                        
            b = mu_X - mu_t * df_Xtrend_code_per$trend
            
            df_Xtrend$intercept[id] = b
        } 
    }
    return (df_Xtrend)
}


get_period = function (per, df_Xtrend, df_XEx, df_Xlist) {

    df_Xtrend = tibble(df_Xtrend)
    df_Xtrend$period_start = as.Date("1970-01-01")
    df_Xtrend$period_end = as.Date("1970-01-01")

    df_Xlisttmp = reprepare(df_XEx, df_Xlist, colnamegroup=c('code'))
    df_XExtmp = df_Xlisttmp$data

    for (g in df_Xlisttmp$info$group) {

        df_XExtmp_code = df_XExtmp[df_XExtmp$group == g,]
        
        iStart = which.min(abs(df_XExtmp_code$Date
                               - as.Date(per[1])))
        iEnd = which.min(abs(df_XExtmp_code$Date 
                             - as.Date(per[2])))

        id = which(df_Xtrend$group1 == g)
        
        df_Xtrend$period_start[id] =
            as.Date(df_XExtmp_code$Date[iStart])
        df_Xtrend$period_end[id] =
            as.Date(df_XExtmp_code$Date[iEnd])
    }
    return (df_Xtrend)
}



get_break = function (df_data, df_meta, p_thresold=0.05) {
    
    # Get all different stations code
    Code = levels(factor(df_meta$code))
    nCode = length(Code)

    date_break = list()
    Code_break = c()
    for (code in Code) {
        
        df_data_code = df_data[df_data$code == code,] 
        df_data_codeNoNA = df_data_code[!is.na(df_data_code$Qm3s),]

        res_break = pettitt.test(df_data_codeNoNA$Qm3s)

        p_value = res_break$p
        nbreak = res_break$nobs
        ibreak = res_break$estimate

        if (length(ibreak) > 1) {
            ibreak = ibreak[1]
        }
        # step1 = mean(df_data_codeNoNA$Qm3s[1:ibreak])
        # step2 = mean(df_data_codeNoNA$Qm3s[(ibreak+1):nbreak])
        if (p_value <= p_thresold) {
            date_break = append(date_break, 
                                df_data_codeNoNA$Date[ibreak])
            Code_break = append(Code_break, code)
        }
    }
    df_break = tibble(code=Code_break, Date=as.Date(date_break))

    return (df_break)
}



get_QAtrend = function (df_data, period, p_thresold) {
    # AVERAGE ANNUAL FLOW : QA #
    
    period = as.list(period)
    
    Imax = 0
    df_QAtrendB = tibble()

    for (per in period) {
               
        df_QAlist = prepare(df_data, colnamegroup=c('code'))

        df_QAEx = extract.Var(data.station=df_QAlist,
                              funct=mean,
                              timestep='year',
                              period=per,
                              pos.datetime=1,
                              na.rm=TRUE)

        df_QAtrend = Estimate.stats(data.extract=df_QAEx,
                                      level=p_thresold)

        I = interval(per[1], per[2])
        if (I > Imax) {
            Imax = I
            df_QAlistB = df_QAlist
            df_QAExB = df_QAEx
        }

        df_QAtrend = get_period(per, df_QAtrend, df_QAEx, df_QAlist)
        


        df_QAtrendB = bind_rows(df_QAtrendB, df_QAtrend)
            
    } 
    
    res_QAtrend = clean(df_QAtrendB, df_QAExB, df_QAlistB)

    return (res_QAtrend)
}



get_QMNAtrend = function (df_data, period, p_thresold) {
    # MONTHLY MINIMUM FLOW IN THE YEAR : QMNA #

    period = as.list(period)
    
    Imax = 0
    df_QMNAtrendB = tibble()

    for (per in period) {

        df_QMNAlist = prepare(df_data, colnamegroup=c('code'))
        
        # df_QMNAEx = extract.Var(data.station=df_QMNAlist,
        #                         funct=mean,
        #                         period=per,
        #                         timestep='month',
        #                         pos.datetime=1,
        #                         na.rm=TRUE)

        df_QMNAEx = extract.Var(data.station=df_QMNAlist,
                                funct=mean,
                                period=per,
                                timestep='year-month',
                                per.start="01",
                                pos.datetime=1,
                                na.rm=TRUE)
        
        df_QMNAlist = reprepare(df_QMNAEx, df_QMNAlist, colnamegroup=c('code'))
        
        df_QMNAEx = extract.Var(data.station=df_QMNAlist,
                                funct=min,
                                period=per,
                                timestep='year',
                                pos.datetime=1,
                                na.rm=TRUE)
        
        df_QMNAtrend = Estimate.stats(data.extract=df_QMNAEx,
                                      level=p_thresold)
        
        I = interval(per[1], per[2])
        if (I > Imax) {
            Imax = I
            df_QMNAlistB = df_QMNAlist
            df_QMNAExB = df_QMNAEx
        }

        df_QMNAtrend = get_period(per, df_QMNAtrend, df_QMNAEx,
                                  df_QMNAlist)

        df_QMNAtrendB = bind_rows(df_QMNAtrendB, df_QMNAtrend)
    }
    
    res_QMNAtrend = clean(df_QMNAtrendB, df_QMNAExB, df_QMNAlistB)

    return (res_QMNAtrend)
}


get_VCN10trend = function (df_data, df_meta, period, p_thresold) {
    # MINIMUM 10 DAY AVERAGE FLOW OVER THE YEAR : VCN10 #

    # Get all different stations code
    Code = levels(factor(df_meta$code))

    df_data_roll = tibble()

    for (c in Code) {
        df_data_code = df_data[df_data$code == c,]
        
        df_data_code = tibble(Date=rollmean(df_data_code$Date,
                                            10,
                                            fill=NA),
                              Qm3s=rollmean(df_data_code$Qm3s, 
                                            10,
                                            fill=NA),
                              code=c)

        df_data_roll = bind_rows(df_data_roll, df_data_code)
    }

    period = as.list(period)
    
    Imax = 0
    df_VCN10trendB = tibble()
    
    for (per in period) {
        
        df_VCN10list = prepare(df_data_roll, colnamegroup=c('code'))

        df_VCN10Ex = extract.Var(data.station=df_VCN10list,
                                 funct=min,
                                 period=per,
                                 timestep='year',
                                 pos.datetime=1,
                                 na.rm=TRUE)

        df_VCN10trend = Estimate.stats(data.extract=df_VCN10Ex,
                                      level=p_thresold)

        I = interval(per[1], per[2])
        if (I > Imax) {
            Imax = I
            df_VCN10listB = df_VCN10list
            df_VCN10ExB = df_VCN10Ex
        }

        df_VCN10trend = get_period(per, df_VCN10trend, df_VCN10Ex,
                                   df_VCN10list)

        df_VCN10trendB = bind_rows(df_VCN10trendB, df_VCN10trend)
    }
    
    res_VCN10trend = clean(df_VCN10trendB, df_VCN10ExB, df_VCN10listB)

    return (res_VCN10trend)
}