sebkcstack: Stacking, gap-filling, cloud removal of Landsat image ET...
In gowusu/sebkc: The Surface Energy Balance and Crop Coefficient Estimation with R

sebkcstack

R Documentation

Stacking, gap-filling, cloud removal of Landsat image ET Model

Description

This function prepares landsat 5, 7, and 8 data for landsat578. First, it reads meta data and returns many input parameters for landsat578 and sebal. Second, it stacks 7 landsat layers: it stacks bands 1-7 for landsat 5 and 7; and bands 2-7,10 for landsat 8.. Third, it removes landsat clouds based on Martinuzzi et al(2009) method. Fourth, it gap-fills landsat 7 strips due to SLC-off as well as gap-filling NAs in other landsat sensors. It can also process any selected bands.

Usage

sebkcstack(folder, meta_pattern = "MTL.txt", remove_cloud = F,
  gap_fill = F, gap_loop = 8, clip = NULL)

## Default S3 method:
sebkcstack(folder, meta_pattern = "MTL.txt",
  remove_cloud = F, gap_fill = F, gap_loop = 8, clip = NULL)

Arguments

`folder`	The folder or directory of landsat files
`meta_pattern`	The regular expression pattern to identify metadata file. The default is "MTL.txt". The function works on the new landsat metadata only.
`remove_cloud`	TRUE FALSE, 1, or 2. To indicate the cloud cover removal from the image. Default is FALSE. If it is set to 1, the overlapping areas of band 1 DN values between 120 and 255 and band 6 DN values of 102 to 128 are used. If it is set to 2 the union of the DN ranges are used; and clouds as well as urban, barren, quarries, rocks, and sand are removed; otherwise only clouds are removed. See Martinuzzi et al(2009) for more details. At the moment only landsat 5 and 7 clouds are removed.
`gap_fill`	Logical (TRUE or FALSE).It replaces strips in landsat 7 or NAs in other data set. It uses `raster{focal}` neighbourhood approach. It is an automated Version of USGS "Gap-Filling Landsat 7 SLC-off Single Scenes Using Erdas Imagine TM". Like USGS, it also takes approximately one hour to complete. see details at http://landsat.usgs.gov/ERDAS_Approach.php
`gap_loop`	numeric. The number of loops or repetitions that gap-fill should be run. The default is 8 for one landsat scene. If the landsat image is smaller, it can be reduced.
`clip`	extent object or raster object or polygon from which an Extent object can be extracted. A polygon or raster will be reprojected to conform the data to be cropped. for example clip can take the form of c(xmin, xmax, ymin, ymax)

Details

The function can simulate any of the activities described in the description section. It takes several minutes to replace strips (1 hour) and remove clouds (30 minutes) on one landsat scene. But stacking of bands and reading of metadata take few seconds. One can save the stacked and processed data in the same "folder" with writesebkc. The output file name is "sebkcstack.tif".

Value

data: raster stacked data. If crop is not NULL then crop Extent object is returned
brescale: brescale of the stacked data
grescale: grescale of the stacked data
sunelev: sun elevation for stacked data
date: Acquired date of the raster stacked data
viewangle: view angle of landsat 8
azimuth: azimuth angle of the image
sensor: Type of satellite
K1: K1 of landsat 8 thermal band 10
K2: K2 of landsat 8 thermal band 10
cc: cloud cover percentage
quality: Image quality
row: WRS_ROW of the image
path: WRS_PATH of the image

Author(s)

George Owusu

References

Martinuzzi, S., Gould, W.A., Ramos Gonzales, O.M. 2007. Creating Cloud-Free Landsat ETM+ Data Sets in Tropical Landscapes: Cloud and Cloud-Shadow Removal. USDA Forest Service General Technical Report IITF-GTR-32.

USGS Using Landsat 7 Data http://landsat.usgs.gov/ERDAS_Approach.php

Examples

## Not run: 
folder=system.file("extdata","stack",package="sebkc")
stack=sebkcstack(folder=folder)
#returns data and grescale
stack$data
stack$grescale

## End(Not run)

gowusu/sebkc documentation built on July 28, 2023, 11:44 a.m.