In this recipe, we will create PLPGSQL functions that implement three noise-based obfuscation mechanisms: Rand, N-Rand, and Pinwheel. Then we will create a trigger function for a table in order to alter all newly inserted points. For this chapter, we will reuse the rk_track_points dataset used in Chapter 3, Working with Vector Data – The Basics.
In this recipe, we will use the ST_Project function to add noise to a single point. Then, we will compare the original data with obfuscated data in QGIS. Finally, we will show the impact of noise filtering on the obfuscated data.
You will also need to extract the data/chp03/runkeeper-gpx.zip file to working/chp12/runkeeper_gpx.
In the recipe, we will use some of the same steps as in ...
