This worksheet covers the correction of the noticeable white stripes in some of the aerial images of the Marburg university forest data set.
After completing this worksheet, you should be able to apply some data value manipulation or algorithm to raster data sets using R.
GIS — most commercial or open source GIS systems will be fine. For open source software running on Ubuntu Linux, the Ubuntu GIS package is a good choice. For Windows, it will be a good choice installing everything via the OSGeo4W environment and not individually. Actually both repositories make available a comprehensive bundle of GI -tools and software packages. We will focus on GRASS, QGIS and SAGA. On the commercial side, ArcGIS is one of the powerful options.
R Studio — we recommend to use R Studio for (interactive) programming with R. You can download R Studio from the official web page.
If you visualize your aerial images in a GIS, a noticeable feature in some of the aerial images from our study area are rather broad white stripes which must be removed somehow.
Please identify the reason for the white boarders and sketch a potential solution which will remove the boarders but preserves the general geometry of the aerial images tiles of 2 by 2 km.
Write an R script which solves the problem according to your sketch. Please make sure that the new raster files do not overwrite the original ones by e.g. saving the new files into a folder called “aerial_merged”. Mark the original and no longer necessary files with the suffix “deprc”.