What is layerstack?
Layer stacking is a process of combining multiple separate bands in order to produce a new multi band image. This type of multi band images are useful in visualizing and identifying the available Land Use Land Cover classes. In order to layer-stack, multiple image bands should have same extent (no. of rows and columns).
How many bands should be stacked?
Mostly satellite images comes in a zipped folder of multiple bands like 11 or 13. In order to save the processing time, one should stack the necessary bands only. For instance, LULC extraction or agriculture acreage estimation require only blue, green red and NIR bands. So one can stack those bands only.
Sentinel-2 image bands-
Sentinel-2 images are provide by ESA in jp2 (JPEG 2000) format. Many software are not capable of reading those images with their projection information intact. Though software are upgrading to process this data but programming is always a better and reliable way to perform actions in a quick and more efficient manner. Sentinel 2 satellite data has band number 2,3,4 and 8 as blue, green red and NIR bands. These bands have same resolution (10 m). So it’s better to stack these bands only if they serve your purpose. Other wise, in order to layer stack all the Sentinel-2 image bands, one should first re-sample all bands into same spatial resolution then apply layer stack technique.
Layer stacking of sentinel-2 image bands-
Few lines code in R can do the layer stack in minutes. It will read projection info automatically.
Code:-
Mitali Chandra,
Associate Editor,
New Delhi,
INDIA
