inst/doc/openeo-04-process_graph_concepts.R

In openeo: Client Interface for 'openEO' Servers

## ---- evi_example, eval=FALSE-------------------------------------------------
#  library(openeo)
#  # EVI example to create a user-defined processes
#  con = connect("openeo.cloud")
#  
#  p = processes()
#  
#  evi_function = function(x,context) {
#    b02 = x[1]
#    b04 = x[2]
#    b08 = x[3]
#  
#    2.5*((b08-b04)/sum(b08,6*b04,-7.5*b02,1))
#  }
#  
#  login()
#  
#  evi_process = create_user_process(evi_function,id = "evi",summary = "Function to be used in a band reducing function with an array of three input values as B02,B04 and B08 of a Sentinel-2 data set.")
#  evi_process

## ---- eval=FALSE--------------------------------------------------------------
#  library(openeo)
#  con = connect("openeo.cloud")
#  p = processes()
#  coll = list_collections()
#  
#  data = p$load_collection(id = coll$SENTINEL2_L2A_SENTINELHUB, bands = c("B02","B04","B08"))
#  class(data)

## ---- eval = FALSE------------------------------------------------------------
#  library(openeo)
#  con = connect("openeo.cloud")
#  p = processes()
#  coll = list_collections()
#  
#  # as starting point: process(argument[s]) --> data
#  data = p$load_collection(id = coll$SENTINEL2_L2A_SENTINELHUB,temporal_extent = c("2021-05-01","2021-08-31"), band = c("B04","B08"))
#  
#  # as modifier: process(data, argument[s]) --> data
#  temporal_subset = p$filter_temporal(data = data, extent=c("2021-05-01","2021-08-31"))
#  
#  # as modifier with process graph: process(data, arguments, process) --> data
#  ndvi_data = p$reduce_dimension(data=temporal_subset,dimension=c("t"),reducer = function(x, ...) {
#    b04 = x[1]
#    b08 = x[2]
#  
#    (b08-b04)/(b08+b04)
#  })
#  
#  # scalar processes
#  p$add(x=2,y=4) # usually used in the former R syntax to manipulate data arrays
#  
#  # as save / serializer: process(data, argument[s]) --> void
#  result = p$save_result(data=ndvi_data, format = "GTiff")

## ---- include=FALSE-----------------------------------------------------------
library(openeo)
openeo:::demo_processes()

## -----------------------------------------------------------------------------
describe_process("load_collection")

## -----------------------------------------------------------------------------
library(sf)
p = processes()

bbox = st_bbox(c(xmin=7,xmax=7.5,ymin=52,ymax=52.5))
st_crs(bbox) = 4326

dc = p$load_collection(id = "S2", spatial_extent = bbox,temporal_extent = list("2022-05-20","2022-06-10"))
dc

## -----------------------------------------------------------------------------
dc$parameters$bands = c("B04","B08")
dc

## -----------------------------------------------------------------------------
dc$parameters$temporal_extent = c("2022-05-01",NA)
dc

## -----------------------------------------------------------------------------
dc$parameters$spatial_extent

## -----------------------------------------------------------------------------
bbox_var = create_variable(name="bbox",description = "The bounding box of the process graph")

dc$parameters$spatial_extent = bbox_var
dc

## -----------------------------------------------------------------------------
ndvi_prep_loader = as(dc,"Process")
ndvi_prep_loader