TideDataR.Rmd

---
title: "TideDataR"
output: github_document
---

Prepare tide data in R.

Read data.

```{r}
library(wrapr)

files <- list.files('tide_data',
               pattern='.*.csv') %.>%
  sort(.)

dat_list <- lapply(
  files,
  function(fi) {
     read.csv(paste0('tide_data/', fi),
              strip.white = TRUE, 
              na.strings = c("", "NA", "-"),
              stringsAsFactors = FALSE)
  })

tides = do.call(rbind, dat_list)
tides['tide_feet'] <- tides['Verified..ft.']
missing_v = is.na(tides['tide_feet'])
tides['tide_feet'][missing_v] <- tides['Preliminary..ft.'][missing_v]
summary(tides['tide_feet'])
```

```{r}
tides['dt'] <- as.POSIXct(paste(tides[['Date']], tides[['Time..GMT.']]), 
                          tz = "UTC")
head(tides)
```

```{r}
deltas <- difftime(tides[['dt']][-1], 
                   tides[['dt']][-length(tides[['dt']])], 
                   units='secs')
summary(as.numeric(deltas))
```

```{r}
saveRDS(tides, 'tides.RDS')
```