openeo client draft

gistfile1.txt

library(openeo) # make the openEO api functions available to the user

eo = openeo_connect("http://.../api/v0", user = "edzer", passwd = "****") # auth
# R6 object with reference semantics / encapsulated OOP

eo$datasets() # list/describe data sets available:
# Sentinel2A-L1C
# Proba-V
# ...

eo$processes() # list available processes

eo$data("Sentinel2A-L1C")
summary(eo$data)

# band 1: 443.9 nm, res: 60 m
# band 2: 496.6 nm, res: 10 m
# band 3: 560 nm,   res: 10 m
# ...

# OK, so we have nir in 8 and  red in 4

eo$filter_bbox()
# filter_bbox:
#  - imagery:  input imagery
#  - left: left boundary
#  - right: right boundary
#  - top: top boundary
#  - bottom: bottom boundary
#  - srs: spatial ref sys


eo$filter_daterange()
# filter_daterange:
#  - imagery: ... 
#  - from: ...
#  - to: ...

eo$NDVI()
# NDVI: 
#  - imagery: ...
#  - red: red band reference (number)
#  - nir: nir band reference (number)

eo$min_time()
# min_time:
#  - time_series: input time series

## OK, so we have all this! Let's do the job:

image = eo$open("Sentinel2A-L1C") # proxy object
summary(image)
# ... bounding box, time range, bands, ...

# nested function call:
#c4 = eo$min_time(
#  eo$NDVI(
#    eo$filter_daterange(
#      eo$filter_bbox(image,
#	    left = 16.1, right = 16.6, top = 48.6, bottom = 47.9, srs = "EPSG:4326"),
#      from = "2017-01-01", to = "2017-01-31"),
#  red = 4, nir = 8)
#)

# or sequential:

c0 = eo$open("/Sentinel2A-L1C")
c1 = c0$filter_bbox(left = 16.1, right = 16.6, top = 48.6, bottom = 47.9, srs = "EPSG:4326")
c2 = c1$filter_daterange(from = "2017-01-01", to = "2017-01-31")
c3 = c2$NDVI(red = 4, nir = 8),
c4 = c3$min_time()

# or in a single call:
c4 = eo$open("/Sentinel2A-L1C")$filter_bbox(
		left = 16.1, right = 16.6, top = 48.6, bottom = 47.9, srs = "EPSG:4326"
	)$filter_daterange(from = "2017-01-01", to = "2017-01-31")$NDVI(
		red = 4, nir = 8)$min_time() 

# or more generically:
c4 = eo
	$filter("/Sentinel2A-L1C")
	$filter(st_bbox(minx = 16.1, maxx = 16.6, miny = 48.6, maxy = 47.9, srs = st_crs(4326)))
	$filter(c(as.Date("2017-01-01"), as.Date("2017-01-31"))
	$filter(bands = c("red", "nir"))
	$map("bands", "/")
	$map("time", "min")


# nothing is computed so far...

plot(c4$fetch_sample(1e6)) # will have like 1e6 pixels to show, not the whole scene;
   # evaluates locally

# push job, compute remotely, download full result
plot(c4$fetch()) # full image (if held in memory)

fetch(c4$openeo, dst = "local_file.png") # if too large to handle in memory