first_try.qmd

---
title: "Exploring EOPF Sentinel Zarr STAC API with R"
format: html
---

# Trying a simple query, download, and visualization


Load potentially useful packages

```{r}
library(sf)
library(rstac)
library(terra)
library(stars)
library(mapview)
```



Set data source (EOPF Sentinel Zarr Samples)
```{r}
stac_source <- stac("https://stac.core.eopf.eodc.eu/")
str(stac_source)
```

Get a brief overview of the collection
```{r}
get_request(stac_source)
```

```{r}	
collections_query <- stac_source |>
  rstac::collections()

collections_query
str(collections_query)
available_collections <- rstac::get_request(collections_query)
available_collections
```	


Search Sentinel-2 L2A data for Münsterland in 2024
```{r}
search_query <- stac_search(
    stac_source,
    collections = "sentinel-2-l2a",
    datetime = "2024-01-01T00:00:00Z/2024-12-31T23:59:59Z",
    bbox = c(6.8, 51.8, 7.8, 52.4),
    limit = 25
  )
executed_query <- get_request(search_query)

```


Download the assets B2, B3, B4 and B8 in 10m resolution

```{r}
download_dir <- file.path(getwd(), "sentinel_zarr")
if (!dir.exists(download_dir)) {
  dir.create(download_dir)
}

rstac::assets_download(items = executed_query, asset_names = c("B02_10m", "B03_10m", "B04_10m", "B08_10m"),
  output_dir = download_dir,
  overwrite = TRUE,
)

```
--> this does not work (under Windows). Maybe it´s because `rstac::assets_download()` seems to create  subdirectories with names taken form the items href, which in this case contains colon characters that are not allowed in Windows folder names.