A preprocessing of remote sensing data is a crucial step in every analytical workflow, and can possibly be the most time consuming one.
Anyway, we want to focus on converting the just-downloaded Landsat 8 and Sentinel 2 products into GeoTIFF files and the visualization in R and QGIS. The pre-processing of Sentinel 1 is a bit more complex. For this purpose, we derive the intensity images on the basis of GRD scenes.
Chapter in a Box
In this chapter, the following content awaits you:
Preprocess Landsat 8
– unzip downloaded image data products
– stack all bands of interest into a rasterstack and save it
– create pyramid layers for rasterstacks
– automate everything for BIG DATA analysis using R
Preprocess Sentinel 2
– convert image data from SAFE to tif format
– resample image data to uniform geometrical resolution
– automate everything for BIG DATA analysis using SNAP and GPT/ R
Preprocess Sentinel 1
– generate intensity images in different polarizations
– expand feature space of S1 intensity images via texture metrics (GLCM)
Visualization
– use R and QGIS for visualization of Landsat 8 data
The basic understanding of the various operators and data types in R is required. If you want to refresh this knowledge, you can now go to the R Crash Course!