TheiaQuery {theiaR}

A query to the Theia website

Description

Generate an send a query to Theia web API to get and download tiles based on input given by the user.

Usage

   q <- TheiaQuery$new(query)

   q$update_token()
   q$submit()

Arguments

q:

A TheiaQuery object

query:

list, the users' request, see 'Queries' for more informations

Details

TheiaQuery$new() Create a new instance of the class, parse 'query' list and submit the query to Theia to retrieve files catalog

q$submit() Submit the query to Theia and get a list of tiles corresponding to search criteria

Queries

Search criteria are given with a 'list' accepting these fields:

• collection: The collection to look for. Accepted values are: 'SENTINEL2', 'LANDSAT', 'Landsat57', 'SpotWorldHeritage', 'Snow'. Defaults to 'SENTINEL2'

• platform: The platform to look for. Accepted values are: 'LANDSAT5', 'LANDSAT7', 'LANDSAT8', 'SPOT1', 'SPOT2', 'SPOT3', 'SPOT4', 'SPOT5', 'SENTINEL2A', 'SENTINEL2B'

• level: Processing level. Accepted values are: 'LEVEL1C', 'LEVEL2A', LEVEL3A', 'N2A'. Defaults to 'LEVEL2A' (or 'N2A' if querying Landsat57 collection).

• town: The location to look for. Give a common town name.

• tile: The tile identifier to retrieve.

• start.date: The first date to look for (format: YYYY-MM-DD).

• end.date: The last date to look for (format: YYYY-MM-DD). Must be after start.date. Defaults to today's date.

• latitude: The x coordinate of a point

• longitude: The y coordinate of a point

• latmin: The minimum latitude to search

• latmax: The maximum latitude to search

• lonmin: The minimum longitude to search

• lonmax: The maximum longitude to search

• orbit.number: The orbit number

• rel.orbit.number: The relative orbit number

• max.clouds: The maximum of cloud cover wanted (0-100)

• max.records: The maximum of tiles to search

See Also

https://github.com/olivierhagolle/theia_download for an alternative download method based on Python. Inspiration for this function.

Examples

# Create a query to Theia database, looking for tiles from Sentinel2
# satellite around Grenoble, between 2018-07-01 and 2018-07-06.

query <- list(collection = "SENTINEL2",
              town       = "Grenoble",
              start.date = "2018-07-01",
              end.date   = "2018-07-06")
q <- TheiaQuery$new(query)

# Show informations on found tiles
print(q$tiles)