VizQ: A System for Scalable Processing of Visibility Queries in 3D Spatial Databases.

In this demonstration, we present VizQ, an efficient, scalable, and interactive system to process and visualize a comprehensive collection of novel visibility queries in the presence of obstacles in 3D space. Specifically, we demonstrate four types of query processing: (i) k Maximum Visibility Query (kMVQ), that finds k locations with the maximum visibility of a target object (ii) Visibility Color Map (VCM), where each point in the space is assigned a color value denoting the visibility measure of the target (iii) Continuous Maximum Visibility (CMV) that continuously finds the location that provides the best view of a moving target, and (iv) Text Visibility Color Map (TVCM), where VCM is generated considering readability of text data displayed on a target. We are the first to propose efficient algorithms to run all of the above four types of visibility queries in the context of a large number of 3D obstacle database. We exploit human visibility metrics to design our data structures and algorithms to efficiently process queries, and our approaches outperform baseline approaches in several order of magnitude both in terms of I/Os and processing time. The link of our demonstration video is https://youtu.be/rcizJtFvQfU.