Book Image

PostGIS Cookbook - Second Edition

By : Pedro Wightman, Bborie Park, Stephen Vincent Mather, Thomas Kraft, Mayra Zurbarán
Book Image

PostGIS Cookbook - Second Edition

By: Pedro Wightman, Bborie Park, Stephen Vincent Mather, Thomas Kraft, Mayra Zurbarán

Overview of this book

PostGIS is a spatial database that integrates the advanced storage and analysis of vector and raster data, and is remarkably flexible and powerful. PostGIS provides support for geographic objects to the PostgreSQL object-relational database and is currently the most popular open source spatial databases. If you want to explore the complete range of PostGIS techniques and expose related extensions, then this book is for you. This book is a comprehensive guide to PostGIS tools and concepts which are required to manage, manipulate, and analyze spatial data in PostGIS. It covers key spatial data manipulation tasks, explaining not only how each task is performed, but also why. It provides practical guidance allowing you to safely take advantage of the advanced technology in PostGIS in order to simplify your spatial database administration tasks. Furthermore, you will learn to take advantage of basic and advanced vector, raster, and routing approaches along with the concepts of data maintenance, optimization, and performance, and will help you to integrate these into a large ecosystem of desktop and web tools. By the end, you will be armed with all the tools and instructions you need to both manage the spatial database system and make better decisions as your project's requirements evolve.
Table of Contents (18 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Adding noise to protect location data


Some of the mechanisms designed for location privacy protection are based on location obfuscation, which is explained in [5] as the means of deliberately degrading the quality of information about an individual's location in order to protect that individual's location privacy.

This is perhaps the simplest way to implement location privacy protection in LBISs because it has barely any impact on the server-side of the application, and is usually easy to implement on the client-side. Another way to implement it would be on the server-side, running periodically over the new data, or as a function applied to every new entry.

The main goal of these techniques is to add random noise to the original location obtained by the cellphone or any other location-aware device, so as to reduce the accuracy of the data. In this case, the user can usually define the maximum and/or minimum amount of noise that they want to add. The higher the noise added, the lower the quality...