6 Downsampling

6.1 Down-sampling (MEAN wets)

**Katie's Notes:**
Right now the files are logging every 10 minutes, which is too high of a resolution. Need to down-sample the dataset from 10min to some other interval that is meaningful to define states to.

12hrs seems too long given how far birds can move in this time, but 10min is far too short.

Tempted to use 2hr resolution to match GPS. 

NOTE: wet values should be summed when down-sampling for calculating proportions, and not mean wets.

6.1.1 2hr Periods

source(here::here("utils/downsample_deg.R"), echo = F)

## 
## =================================================== 
##            YOU LOADED downsample_deg            
##    view this function in wey-dry_analysis/R/utils   
## =================================================== 
## 
## this function subsamples DEG files by an allotted time period
## Combines each 10 minute period into X hr periods
## (define X using bin_time), and takes the sum of
## wets0-20 for each bin_time period.
## 
## 
## - Ensure dependencies in project_settings.R
## - Define downsampled.dir in project_settings.R
## =============================================

bin_time = 2

#define deg files to use
deg_files <- list.files(output.dir, pattern = "*.deg", full.names = TRUE)#[1:10] #add if you want to subset

#set up a furrr plan for using 4 cores
plan(multisession, workers = 4)

deg_2hrs <- future_map(deg_files, downsample_deg, bin_time = bin_time, .progress = TRUE)

plan(sequential)

wets = 0 means 10min interval was entirely dry wets = 20 means 10min interval was entirely wet

For one 10min interval,
if wets=1, then 600s/20 = 30 seconds
so 1 unit wets = 30 seconds wet per 10min interval

So our dataset’s wets values now represent the average number of 10-minute intervals that were wet during the 2-hour period. This means each 2hr period has 12 intervals of 10 minutes (600 secs).