[USGS-R#49] add explanation about python envs/dependencies

1_network/src/catchment_attributes.R

@@ -1,7 +1,15 @@
 # The purpose of these functions is to interface between
 # the scipiper pipeline and the Python code
 download_and_combine_sb_attr_data <- function(out_ind) {
-    reticulate::use_condaenv("rgcn")
+    # reticulate will try to find a python executable to 
+    # run the python functions. If the one it finds doesn't
+    # have the required libraries (see environment.yml) then
+    # it will cause an error (ModuleNotFound). In that case,
+    # you can either install the required packages in the Python
+    # environment that it is using via pip or conda, or you can
+    # create a conda environment from the projects environment.yml
+    # file and then tell reticulate to use that environment via
+    # reticulate::use_condaenv("drb_prep")
     out_file <- as_data_file(out_ind)
     catch_attr_py <-
         reticulate::import_from_path('catch_attr', path = '1_network/src/')
@@ -12,7 +20,6 @@ download_and_combine_sb_attr_data <- function(out_ind) {
 
 relate_attr_to_drb_segs <-
     function(out_ind, all_attr, geofabric, drb_network) {
-        reticulate::use_condaenv("rgcn")
         out_file <- as_data_file(out_ind)
         attr_file <- as_data_file(all_attr)
         geofab_file <- as_data_file(geofabric)
@@ -31,7 +38,6 @@ relate_attr_to_drb_segs <-
 
 
 fetch_combine_catch_attr_metadata <- function(out_ind) {
-    reticulate::use_condaenv("rgcn")
     out_file <- as_data_file(out_ind)
     catch_attr_py <-
         reticulate::import_from_path('catch_attr', path = '1_network/src/')