docs(vignette niveaux nappes): refine and set data cache package

Refs #42

data-raw/vignette_example_niveaux_nappes_api.R

@@ -1,27 +1,43 @@
 ## code to prepare `vignette_example_niveaux_nappes_api` dataset goes here
 library(hubeau)
+library(dplyr)
 
 my_water_table_code <- "GG063"
 
 stations <- get_niveaux_nappes_stations(
   codes_masse_eau_edl = my_water_table_code
 )
 
-water_table_level <- map_df(.x = stations$code_bss,
-                            .f = function(x) get_niveaux_nappes_chroniques(code_bss = x,
-                                                                           date_debut_mesure = "2015-01-01"))
+water_table_level <- purrr::map_df(
+  .x = stations$code_bss,
+  .f = function(x)
+    get_niveaux_nappes_chroniques(code_bss = x,
+                                  date_debut_mesure = "2015-01-01")
+)
 
 water_table_level <- water_table_level %>%
   mutate(date_mesure = lubridate::ymd(date_mesure),
          year = lubridate::year(date_mesure),
          month = lubridate::month(date_mesure))
 
+yearly_mean_water_table_level <- water_table_level %>%
+  group_by(code_bss,
+           year) %>%
+  summarise(n_months = n_distinct(month)) %>%
+  filter(n_months == 12) # complete years
 
-vignette_example_niveaux_nappes_api <- list(
-  stations = stations,
-  water_table_level = water_table_level
-)
+yearly_mean_water_table_level <- yearly_mean_water_table_level %>%
+  select(-n_months) %>%
+  left_join(water_table_level) %>% # filtering join
+  group_by(code_bss,
+           year,
+           month) %>%
+  summarise(monthly_mean_water_table_level = mean(niveau_nappe_eau, na.rm = TRUE)) %>%
+  group_by(code_bss,
+           year) %>%
+  summarise(yearly_mean_water_table_level = mean(monthly_mean_water_table_level, na.rm = TRUE)) %>%
+  ungroup()
 
 save(stations,
-     water_table_level,
+     yearly_mean_water_table_level,
      file = "inst/vignettes/example_niveaux_nappes_api.RData")

vignettes/example_niveaux_nappes_api.Rmd

@@ -111,9 +111,10 @@ water_table_level <- water_table_level %>%
          month = lubridate::month(date_mesure))
 ```
 
-Selection, for each of the stations, of the years with 12 months of data. This is done to prevent incomplete time periods to influence the yearly mean water level excessively.
+Selection, for each of the stations, of the years with 12 months of data. 
+This is done to prevent incomplete time periods to influence the yearly mean water level excessively.
 
-```{r}
+```{r, eval = FALSE}
 yearly_mean_water_table_level <- water_table_level %>% 
   group_by(code_bss,
            year) %>%