Bin cast

David Kaiser 14 May 2020

Description

This function is intended be used to "bin" CTD casts by depth. It takes a data frame and a bin depth that specifies the output depth interval. The column of depth values can by specified by name or index, otherwise the first column will be used. If a name is supplied, the column containing the depth bins will be called by this name, if no name or an index is supplid, the column will be called "binned_depth". A call to aggregate() uses this column for binning. The aggregation function can be set, it defaults to mean(). There's an option to output the bin size (number of values in each depth bin) with the result.

Arguments

x -- dataframe containing the cast

bin_depth -- the interval the bins should take, e.g. 0.5 would round to the nearest 0.5 [in units of depth]

depth_fun = mean -- the function to be passed to aggregate, defaults to mean

depth_col = NULL -- name or index of the column containing the depth values, if not supplied first column will be used

bin_size = FALSE -- logical: should a column containing the bin size be attached to the output

Result

A dataframe containing the binned results

Examples

dummy data:

cast <- data.frame(depth = sort(runif(100, min = 0, max = 100)),
                   temp = sort(runif(100, min = 20, max = 30), decreasing = TRUE),
                   sal = sort(runif(100, min = 18, max = 35)))
head(cast)

      depth     temp      sal
1  1.839569 29.98928 18.08924
2  2.504805 29.93909 18.14086
3  3.630907 29.81154 18.23834
4  4.560465 29.78159 18.28353
5  8.472528 29.73549 18.35619
6 10.017403 29.62108 18.47133

binning data

binned_cast <- bin_cast(x = cast, 
                        bin_depth = 10)
head(binned_cast)

  binned_depth     temp      sal
1            0 29.88037 18.18800
2           10 29.44612 19.14264
3           20 28.59929 21.05889
4           30 27.80375 22.34259
5           40 27.18193 23.54558
6           50 25.96970 25.39162

effects of arguments

binned_cast1 <- bin_cast(x = cast, 
                        bin_depth = 2, 
                        depth_col = "depth",
                        bin_fun = median, 
                        bin_size = TRUE)
head(binned_cast1)

  depth     temp      sal bin_size
1     2 29.96419 18.11505        2
2     4 29.79656 18.26094        2
3     8 29.73549 18.35619        1
4    10 29.62108 18.47133        1
5    12 29.45970 19.19519        3
6    14 29.17662 19.84522        2