Convex Hull Visualization
Adam Lee | Published on February 27, 2025
This small project dynamically generates a unique set of points, determines the shortest path to connect and contain all coordinates using a brute force convex hull algorithm approach, and displays a visualization of the result.
Table of Contents
Overview
Computational geometry plays a crucial role in various fields, from computer graphics to robotics and geographic mapping. One fundamental concept within this domain is the convex hull—the smallest convex shape that can enclose a given set of points. In this post, we explore a dynamic convex hull visualization that allows users to see this concept in action.
What is a Convex Hull?
A convex hull is the minimal boundary that encloses a set of points in a plane. Imagine stretching a rubber band around a group of nails on a board; once released, the band forms the convex hull of those points. This structure has applications in collision detection, image processing, and data analysis.
How Does the Visualization Work?
This project provides an interactive convex hull visualization, dynamically computing and displaying the convex boundary as points are generated. The implementation consists of:
Point Generation
Randomly distributing points within a defined area.
Convex Hull Calculation
Utilizing an efficient algorithm to determine the outermost points forming the hull.
Real-time Rendering
Displaying the results dynamically using JavaScript and HTML5.
Algorithm Implementation
The visualization relies on a computational geometry approach to construct the convex hull efficiently. A commonly used method is the Graham’s scan algorithm, which sorts points by their polar angle and constructs the hull iteratively using a stack-based approach. Alternatively, the Jarvis March (Gift Wrapping) algorithm may be employed for simplicity, iteratively selecting the next hull point by checking orientations.
Technology Stack
Backend
PHP is used for generating random points and handling convex hull computations.
Frontend
HTML, CSS, and JavaScript render the visualization interactively.
Graphics
The visualization leverages the HTML5 canvas to dynamically plot points and draw the convex hull.
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