Kevin Byrne’s Study: ESRI Extension Research, 2009


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Kevin Byrne’s Study: ESRI Extension Research, 2009

  1. 1. Extension Research Presentation for Week 2 of Saint Mary U’s Advanced Spatial Modeling ______________________________ Kevin Byrne September 14, 2009  
  2. 2. Goal To provide an overview of a chosen extension by a demo/discussion using a mix of resources.  
  3. 3. Background • Title is An ArcGIS Extension for Generating and Updating Ordinary and Multiplicatively Weighted Voronoi Diagrams for Points, Lines, and Polygons and author is Pinliang Dong • Uses ArcObjects written in Visual Basic • It is raster-based and was posted to ESRI’s website on April 4, 2009. ESRI’s download record shows 1410 so far.  
  4. 4. Background (cont’d) • Voronoi diagrams are tessellations that define regions “such that each contains all locations closer to the generating object than to any other object in the pattern.” • Fall under a large umbrella known as exploratory spatial data analysis (ESDA). • A first – and dramatic – usage was by Dr. John Snow in order to map cholera outbreaks in London in the mid 19th c.  
  5. 5. Background (cont’d) Dong’s extension has the following features: • Works for point, line, and polygon features; • Generates both ordinary and multiplicatively weighted Voronoi diagrams in vector format; • Assigns non-spatial attributes of input features to cells through spatial joining; and… • Produces ordinary or weighted Euclidean distance raster datasets for modeling apps.  
  6. 6. My Methodology-Steps 1. I searched ESRI’ site with the key word voronoi and found one script. The extension to which it linked was downloaded from the site; its size was 3832 k. 2. It needed to be unzipped and installed with a setup.exe routine. I then turned it on as an extension in ArcMap and docked it. 3. The install folder included a) sample data assets, and b) an html tutorial doc. that I used to acquaint myself with its capabilities. 4. I completed the first of three phases of Mr. Dong’s tutorial using his data 5. The final (third) phase of the tutorial was the most interesting; it demanded a deep dive into an attribute table of Dong’s .mxd file in order to explore a target attribute column of one’ choosing. I tried this out as it is a centerpiece to the extension’s strength; results were successful. 6. I saved the completed tutorial’s .mxd file, did screen snaps throughout the procedure, turned on appropriate layers, and exported one Voronoi map to PDF. 7. Lastly I assembled screen snaps, final map, and descriptive textmatter into this final report.  
  7. 7. Discoveries • Download and installation was seamless. • Tutorial was essential. • I hope to try this with my own data but I need more theoretic background. • Its blend of vector and raster output permitted me to explore overlapping two layers with varied transparency. These hybrid displays were visually engaging and informative.    
  8. 8. Voronoi Map With Owner-Occupied Count 3927 3863 9666 5171 10607 10607 3863 6871 8016 7007 8016 7550 Data Source: P. Dong Extension Research, Analysis and Design: K. Byrne Date: September 14, 2009 Course: Advanced Modeling, Saint Mary's U.
  9. 9. References • Dong, P., 2008. Generating and updating multiplicatively weighted Voronoi diagrams for point, line and polygon features in GIS… • Johnson, S., 2006. The Ghost Map: The Story of London's Most Terrifying Epidemic… • O’Sullivan, D. and D. Unwin, 2003. Geographic Information Analysis…