modisRiceValidate: Validates rice from the previously generated rice pixels by...

In RiceMap: Mapping rice area with time series of MODIS images

Description

This function reads the rice pixels generated from Vegetation indices. Then, it validates the rice areas by using Enhanced Vegetation Indices (EVI) calculated per 8-day composite from the previous and current year. It identifies rice pixels by checking the rice temporal pattern using EVI values. This function uses backtracking algorithm which tracks the maximum EVI value, the half of the maximum EVI, and EVI values less than the 0.2 threshold for flooded (Xiao,2006).

Usage

modisRiceValidate(perhapsPath, curYearPath, prevYearPath, outPath, tileNumber, interpolation=NULL)

Arguments

perhapsPath	path with perhapsRice file (possible rice areas).
curYearPath	path with evi tiff files for the current year of the possible rice areas.
prevYearPath	path with evi tiff files for the previous year of the possible rice areas.
outPath	path which the verified rice areas will be stored
tileNumber	vertical and horizontal tile number of MODIS, tileNumber should follow the format in the MODIS filename, e.g. "h29v07"
interpolation	type of interpolation to be used to fill missing data in the time series of EVI values. Can be "linear", "spline", or NULL

Details

Uses EVI images that has been generated by modisVeg as input in verifying MODIS rice areas.

Note

# to use this function, follow these steps:

setwd(dirname(system.file("external/.", package="RemoteSensing")))

# set the perhapsRice directory path # the path varies depending on your Operating System # this one is for Linux system: perhapsPath <- "/home/yann/Desktop/evi/rice"

# In Windows OS: perhapsPath <- "C:\path\of\the\directory\for\perhapsRice" # Note: replace '\' by '\' or '/' so R will be able to read it as directory path

# set directory path of evi tiff files for the current year of the possible rice areas curYearPath <- "/home/yann/Desktop/evi/2007"

# set directory path of evi tiff files for the previous year of the possible rice areas prevYearPath <- "/home/yann/Desktop/evi/2006"

# set directory path of the folder where the output will be saved outPath <- "/home/yann/Desktop/evi/reallyRice"

# set the tile number tileNumber <- "h29v07"

# call this function modisRiceValidate(perhapsPath, curYearPath, prevYearPath, outPath, tileNumber)

Author(s)

Angelo Carlo Pacheco, Jorrel Khalil Aunario

References

Xiao, X., Boles, S., Frolking, S. et.al. 2006. Mapping paddy rice agriculture in Southeast Asia using multi-temporal MODIS images. Remote Sensing of Environment 100, pages, 95-113.

See Also

modisClean, modisVeg

RiceMap documentation built on May 2, 2019, 5:16 p.m.