Algorithm Visualization System for Teaching Spatial Data Algorithms

Abstract

Executive SummaryTRAKLA2 is a web-based learning environment for data structures and algorithms. The system delivers automatically assessed algorithm simulation exercises that are solved using a graphical user interface.In this work, we introduce a novel learning environment for spatial data algorithms, SDA-TRAKLA2, which has been implemented on top of the TRAKLA2 system. Spatial data items are identified by a set of coordinates, such as x and y for two-dimensional spatial data. The spatial environment contains new visualizations for representing spatial data, and a number of new exercises that cover a variety of spatial data algorithms.The new exercises have been used in the spatial data algorithms course at the Helsinki University of Technology since spring 2007. Here, we summarize previous research and report on an analysis of the quantitative data on the students' learning outcomes for years 2007 and 2008. We have also analyzed the students' learning results using qualitative methods in order to discover how the new system affects the students' learning outcomes.Keywords: Algorithm visualization, automatic assessment, learning environments, spatial data algorithms, TRAKLA2 IntroductionSpatial data is data that is located in a multidimensional space (Laurini & Thompson, 1992). In other words, each spatial data item is identified by a set of coordinates, which define its location in relation to other data items. Thus, each spatial data item contains spatial information (coordinates) that describes the location of the item and associated attribute data that describes what it represents. Spatial data is used in numerous disciplines, such as geographic information systems (GIS), computer graphics, robotics, virtual reality, computer-aided design, biology, VLSI design, and many others. In the context of GIS and related disciplines, the data is assumed to model geographic locations on the Earth's surface and their associated properties. In this paper, we discuss spatial data in this context. In GIS, there are at least two coordinate axes (x and y, which represent geographical longitude and latitude), and two additional ones (height and time) can also be used. Spatial data algorithms (SDA) are algorithms designed to process and manipulate such data and spatial data structures are entities used to store the data.Spatial data structures are based on regular non-spatial data structures suchMaterial published as part of this publication, either on-line or in print, is copyrighted by the Informing Science Institute. Permission to make digital or paper copy of part or all of these works for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage AND that copies 1) bear this notice in full and 2) give the full citation on the first page. It is permissible to abstract these works so long as credit is given. To copy in all other cases or to republish or to post on a server or to redistribute to lists requires specific permission and payment of a...