CS 350 (now 3225): Algorithms for Geographic Information Systems (GIS)
(or, A computational perspective of GIS)

Fall 2013: T, Th 1:00 - 2:25 in Searles 126

Geographic Information Systems (GIS) are computer systems for storing, displaying and analyzing geographically referenced, or geospatial data. GIS started many years ago with primitive systems of visualizing maps. In the past twenty years, with the growth of computer technology and the explosion of digital geographic data, GIS have seen a tremendous growth and have established as a field of its own. GIS are used by a growing number of people in earth, atmospheric and oceanographic sciences. Routine GIS tasks range from visualization of various data layers, sensor monitoring, modeling of phenomena like flow, radiation, erosion, deposition, infiltration, visibility, and also network computations like shortest paths, to name just a few.

For the disciplines that use GIS, the study of GIS usually starts with the study of the functionality provided by the standard GIS packages to manage and analyze data and model specific problems. For example, a city planner may want to find the best location to host an ugly construction. How can this problem be modeled with a GIS; What data is available; How can all the layers of data be integrated; Is there a way to model and query the impact of a site.

This class gives a computing perspective of GIS. For Computer Scientists, GIS is a rich source of problems, spanning from theory, to data bases, networks and systems and algorithm engineering. The class introduces the basic problems encountered in designing GIS: data models, data representation and basic algorithms.

The class was developed with the support of NSF award no. 0728780.

Prerequisites: csci210 and csci231 (or permission of instructor). Note: the class will be tailored based on the background and interests of the students.

Instructor: Laura Toma
Office: 219 Searles

Office hours: T, Th 2:30-4 (after class). For quick questions, you can drop by any time I am in the office. Or, send me an email to setup a (different) time.

Class mailing list: csci3225 at bowdoin.edu. Use it to post questions, instead of emailing me separately.

Class webpage: http://www.bowdoin.edu/~ltoma/teaching/cs350/fall13

Tentative course topics:

• A brief C, Linux and OpenGL tutorial/review.
• Some geometric algorithms used in GIS.
  • Fundamental primitives.
  • Finding the closest pair of points.
  • Convex hull. CH lower bound.
  • Line/plane sweep: Horizontal-vertical segment intersection.
  • Line/plane sweep: Finding the intersections of a general set of segments (Bentley-Ottman).
• Geographic data models (raster, vector, TIN) and representation (winged-edge, quad-edge).
• Delaunay triangulation.
• Flow on terrains: Models, computing flow, river network, watersheds, basins.
• Visibility on terrains: Models, algorithms for viewshed, multiple viewsheds, guarding, and approximation.
• Line simplification. Terrain simplification. Grid-to-Tin conversion. LIDAR-to-TIN conversion.
• Quadtrees and applications.
• Image analysis.

Materials: The reading for the class will come from research papers and slides that are available online. Some reference books that I used to prepare the class (none required)

• The C programming Language. Kernighan and Ritchie. Second edition.
• GIS: A computing perspective. Worboys and Dukham. Second edition.
• Algorithmic Foundations of geographic Information Systems.. Kreveld, Nievergelt, Roos, Widmayer Editors. LNCS tutorial.
• Computational geometry. M. de Berg, M. van Kreveld, M. Overmars, O. Schwarzkoph.
• Computational geometry in C. J. O'Rourke.
• Programming pearls. J. Bentley.

Grading policy: The grade will be based on programming projects, project reports and class presentations. There are no exams.