FarmMapsApiClient/FarmmapsDataDownload/ShowGeotiff.r

# ShowGeotiff.r
# Have a look at a downloaded satellite image and check if stats are correctly calculated
# downloaded and calculated the stats for the polygon defined in C:\git\FarmMapsApiClient\FarmmapsDataDownload\DataDownloadInput.json
# and in which in the console I requested the image for date '2022-08-25'

library(terra)
setwd("C:/git/FarmMapsApiClient/FarmmapsDataDownload/bin/Debug/netcoreapp3.1/Downloads")

# FarmmapsDataDownload
fileGeotiff <- "sentinelhub_test_BvdTFieldlabG92_20220825.tif"
lenfilename <- nchar(fileGeotiff)
year <- substr(fileGeotiff,lenfilename-11,lenfilename-8)
imgdate <- substr(fileGeotiff,lenfilename-11,lenfilename-4)

r.sentinelhub <- rast(x=fileGeotiff)
# plot(r.sentinelhub) shows 6 plots (6 bands)
# 1. ndvi
# 2. wdvi Note wdvi-red
# 3. ci-red
# 4. natural: red
# 5. natural: green
# 6. natural: blue
names(r.sentinelhub) <- c("ndvi","wdvired","ci-red","red","green","blue")
# crs(r.sentinelhub)
# CRS arguments: +proj=longlat +datum=WGS84 +no_defs
r.sentinelhub.rd <- project(r.sentinelhub,'+init=EPSG:28992')
# crs(r.sentinelhub.rd)

r.sentinelhub.rd.wdvi <- subset(r.sentinelhub.rd,2)
# dev.off()
plot(r.sentinelhub.rd.wdvi,main=paste("wdvi",imgdate),xlab="RDX",ylab="RDY")
global(r.sentinelhub.rd.wdvi, fun="mean")

# Convert the .rd.wdvi raster to WGS84
r.sentinelhub.wgs84.wdvi <- project(r.sentinelhub.rd.wdvi, '+init=EPSG:4326')

# Draw a polygon on top of the raster
# Polygon pol from C:\git\FarmMapsApiClient_WURtest\FarmmapsDataDownload\DataDownloadInput.json
pol <- data.frame(id = 1, wkt = gsub("\n","",'POLYGON((
      5.563472073408009 52.547554398144172,
      5.567425915520115 52.547725375100377,
      5.567917474269188 52.540608459298582,
      5.563878143678981 52.54048022658143,
      5.563472073408009 52.547554398144172
      ))'))


pol.wgs84 <- vect(pol$wkt,crs='+init=EPSG:4326')
pol.rd <- project(pol.wgs84, "+init=epsg:28992")

# Have a look at both polygons
# wg84
plot(r.sentinelhub.wgs84.wdvi,main=paste("wdvi",imgdate),xlab="LON",ylab="LAT")
plot(pol.wgs84,add=TRUE, col="transparent",border="red")
# RD
plot(r.sentinelhub.rd.wdvi,main=paste("wdvi",imgdate),xlab="RDX",ylab="RDY")
plot(pol.rd,add=TRUE, col="transparent",border="red")

# Clip the polygon from the full rectangle figure
r.sentinelhub.rd.wdvi.pol <- mask(r.sentinelhub.rd.wdvi,pol.rd)
r.sentinelhub.wgs84.wdvi.pol <- mask(r.sentinelhub.wgs84.wdvi,pol.wgs84)
plot(r.sentinelhub.wgs84.wdvi.pol,main=paste("wdvi",imgdate),xlab="LON",ylab="LAT")
plot(pol.wgs84,add=TRUE, col="transparent",border="red")
#That's what we want! 

# Now compare the stats
global(r.sentinelhub.wgs84.wdvi,'mean')	# [1] 0.1733634 # Stats from rectangle, WGS84
global(r.sentinelhub.rd.wdvi,'mean')	# [1] 0.173531 # Stats from rectangle, RD. Almost but not exactly same as above
global(r.sentinelhub.wgs84.wdvi.pol,'mean',na.rm=TRUE)	# [1] 0.1740224 # Stats from raster clipped by polygon, WGS84
global(r.sentinelhub.rd.wdvi.pol,'mean',na.rm=TRUE)	# [1] 0.1738386 # Stats from raster clipped by polygon, RD. Almost but not exactly same as above
# file satelliteStats_test_BvdTFieldlabG92_20220825.csv
# "wdvi" "mean": 0.173905644768987
# Mean in csv corresponds with cellStats calculated from clipped tif!
# So while the tif returned is a non-clipped image, the downloaded statistics are from the clipped image
# Exactly as we wanted.
global(r.sentinelhub.wgs84.wdvi.pol,'median', na.rm=TRUE)	# Error in fun(values(x[[i]]), ...) : could not find function "fun"
r.sentinelhub.wgs84.wdvi.vals <- values(r.sentinelhub.wgs84.wdvi)
median(r.sentinelhub.wgs84.wdvi.vals)	# [1] 0.1459627
median(r.sentinelhub.wgs84.wdvi.vals,na.rm=TRUE)	# [1] 0.1459627
r.sentinelhub.wgs84.wdvi.pol.vals <- values(r.sentinelhub.wgs84.wdvi.pol)
median(r.sentinelhub.wgs84.wdvi.pol.vals)	# [1] NA
median(r.sentinelhub.wgs84.wdvi.pol.vals,na.rm=TRUE)	# [1] 0.1453323