TonyLadson

###########################################################################################
#
#  Fitting non-linear models in R
#  See tonyladson
#  
#  5 June 2016
###############################################################################################
#
# Example data come from Figure 5 from Ian Cordery's thesis
# Also Figure 3 from Cordery, 1970

TonyLadson

#
#  API  - Antecedent Precipitation Index
#
#
#

library(stringr)
library(readr)
library(dplyr)
library(lubridate)

TonyLadson

library(RCurl)
library(jsonlite)
library(stringr)
library(dplyr)
library(ggplot2)



rffe.data <- postForm("http://rffe.arr.org.au/",
                      catchment_name = "test1",

TonyLadson

library(stringr)
library(readr)
library(dplyr)
library(lubridate)
library(ggplot2)
library(scales)
library(treemap)


#__________________________________________________________________________________________

TonyLadson

# Function to calculate 100% saturated dissolved oxygen in mg/L as a function of temperature in degrees Celcius

Calc_DOsat100 = function(temp){

# temp = temperature in degrees C
# relationship between temperature and dissolved oxygen as defined by the APHA
# American Public Health Association (1992)
# Standard methods for the examination of water and wastewater. 18th ed. Washington DC.

# Required constants

TonyLadson

# format_out either 'deg' - decimal degrees, or 'dms' - deg:min:sec

UTM2deg <- function(easting, northing, zone, format_out = c('deg', 'dms')){
  
  format_out <- match.arg(format_out)
  
  # Helper function to convert from decimal dms to dd:mm:ss
  Deg2dms <- function(x){
    dd <- trunc(x)
    mm <- trunc(60*(x - dd))

TonyLadson

# x is a dataframe
Fix_names <- function(x){
  my.names <- make.names(names(x))
  my.names <- str_to_lower(my.names) 
  
  # change multiple consecutive dots to one dot, delete leading and trailing dots  
  
  my.names <- str_replace_all(my.names, c("[.]+" = "\\.", "[.]$" = "", "^[.]" = "")) 
  names(x) <- my.names
  x

TonyLadson

# Function to calculate 100% saturated dissolved oxygen in water in mg/L as a function of temperature in degrees Celcius

Calc_DOsat100 = function(temp){
  
  # temp = temperature in degrees C
  # relationship between temperature and dissolved oxygen as defined by the APHA
  # American Public Health Association (1992)
  # Standard methods for the examination of water and wastewater. 18th ed. Washington DC.
  
  # Required constants

TonyLadson

# Figure 1
# DO - date of sample

WQ %>% 
  ggplot(aes(x = date, y = do.mg.l)) + geom_point() +
  labs(y = 'DO (mg/L)', x = 'Date') +
  theme_grey(base_size = 16)

# Figure 2
# DO - temperature

TonyLadson

# Convert from 'HH:MM:SS' to fractions of a day
# This also works with HH.HHHH
# and is vectorised

Time_convert <- function(x){
  
  f <- function(x,y){
    as.numeric(x)/60 + as.numeric(y)
    }
  split_time <- str_split(x, ':')