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Showing posts from 2019

Gabriel Graph and Stepping Stone Graph

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In the new implemetation of GeoDataAnalysis [1] project, implementations of Gabriel graph [2] and Stepping Stone Graph [3] are available. Also tool bar has been updated with two combo boxes, one for selecting the graph type to be plotted and one for selecting the configuration parameter value for Stepping Stone Graph. Still there are two buttons to plot two point sets, boundary of lake Michigan and an experiment point set. Following is the new user interface. Gabriel graph of lake Michigan Stepping Stone Graph of lake Michigan configuration parameter, d = 2 configuration parameter, d = 4 configuration parameter, d = INFINITY One thing to note about the Stepping Stone Graph when configuration parameter (d) reaches infinity is, it becomes the relative neighbourhood graph [4] . Creating Stepping Stone Graph using the d-spectrum provides an efficient method to calculate the relative nighbourhood graph of a given point set. References [1]  https://github.com/s

S-hull algorithm for creating Delaunay Triangulation

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The  Delaunay triangulation [1] is a useful concept in graph theory and spatial data analysis. S-Hull [2] is a recent algorithm published for faster creation of a Delaunay triangulation of a point set. A Java implementation of S-Hull algorithm can be located at [3] . To try this implementation out, clone the git repository [4] and run it following the instructions in my previous blog post . When you get to the UI, there are two buttons in the tool bar with text labels. When you click on them following Delaunay triangulation will be plotted. References [1] https://en.wikipedia.org/wiki/Delaunay_triangulation [2] https://arxiv.org/abs/1604.01428 [3] https://github.com/sameerak/GeoDataAnalysis/blob/master/src/main/java/au/edu/unimelb/cis/geo/controller/DelaunayTriangulation.java [4] https://github.com/sameerak/GeoDataAnalysis

GPS data analysis using geotools

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This blog post explains the usage of a new GPS data analysis tool [1] created to analyze GPS data, using GeoTools [2] Java libraries. This tool follows the structure of Maven quickstart project structure presented in GeoTools web site [3] .  Java code for the GPS data analysis tool project is available in GitHub repo [1]. This project follows a generic Model-View-Controller (MVC) code structure.  In this structure: (1) View component contains a modules required for User Interface; (2) Controller component contains the modules related to data structures and algorithms; while (3) Model component contains the pathways to resources and utilities that dictate the generic structure of the operation of the tool. Following figure shows the current folder structure of the project. Operation Project is structured as a simple Maven project, so it can be built and used with simple mvn commands.  For anyone unfamiliar with maven, getting-started [4] guide is a good place to start. Ma