1 2012 2 information technologies and control Key Words: Distributed Systems; animation; GIS; animated map; spa- tiotemporal data. Abstract. Maps are an excellent way to present data that have spatial components. However, when the data being presented vary over time, a simple two-dimensional map ignores an important feature of the data. An animated map that shows a series of two-dimensional maps at successive points in time allows one to add a time dimension to the display of data. The study presented in this paper proposes a distributed service-oriented architecture to create map animations from spatiotemporal datasets. We extend open standards’ GIS web services definitions with topic-based publish-subscribe paradigm, which best suits to the animation requirements. The effectiveness of the technique is demonstrated on exploratory data analysis on Turkey’s earthquake seismic data records at the end of the paper. 1. Inroduction Vast amounts of data related to earth are time-series and spatial in nature. The geological studies are mostly based on spatial data analysis. To understand geographical phenomena it is important to show the patterns changing over time. Spatial data are preferably represented and displayed as map layers. When one has the same layer in several different moments along the time, it is better to display them as part of a movie. This is called time-series animation, which is a visualization technique ideally suited for the display and analysis of spatiotemporal and geographic data sets. Map animations enable scientific analysis and results to be understood not only by the scientist but also the public and policymakers from different domains and educa- tion level. Animated maps can be interpreted more easily than their static representations by the users. Interoperability and distributed services are clear trends that today’s Geographic Information Systems (GIS) [1] is taking. Standards for interoperability proposed by distributed frameworks such as the Open Geospatial Consortium (OGC) [2] offer advan- tages for data sharing, for combining software components and for overlaying graphical outputs from different sources. The stan- dardization efforts cause distributed services to be widely ac- cepted and used in many areas such as governmental agencies and educational institutions. However, standardization comes with its cost. Developing OGC compatible GIS services (WMS [3] and WFS [4]) as web services enables them to be discoverable and used in third party distributed systems [5]. However, efficient data transportation capability still remains as a challenge, be- cause of the fact that web services are based on XML based SOAP over HTTP protocol and data to be processed are encoded in Geographic Markup language (GML) [6] which is an XML- based format. To overcome such problems in a distributed sys- tem framework requiring large scale XML-encoded geographic feature sets, we have investigated the possibilities of using topic-based publish-subscribe paradigms (which is mostly used in P2P systems) for exchanging data payload between web services. NaradaBrokering [7] is one of the well-known applica- tions of that approach enabling streaming data transport, reliable delivery and recovery from network failures at the application level. NaradaBrokering is integrated to the system through two- step communication protocol in which standard web service interfaces are used as a handshake protocol and the actual data is transferred over publish-subscribe based messaging system. This approach has some advantages over pure web services. The proposed system gets rid of the SOAP message creation overheads, and even enables creation of map images with par- tially returned data. After developing an efficient data transfer protocol between standard GIS web services, we propose an animation web ser- vice extended from WMS. WMS have capabilities of animating temporally related map images one by one dated in a vertical frame as a film. Images are created from the spatiotemporal data provided by WFS. The effectiveness of the technique is demonstrated on exploratory data analysis on Turkey’s earth- quake seismic data records at the end of the paper. The remainder of this paper is organized as follows. In Section 2, we present the related works. Section 3 presents distributed service oriented architecture for map animations. Section 4 concludes the paper. 2. Related Work In the last decade renewed interest in animation has emerged due to technological developments. Because of these developments it is nowadays relatively easy and inexpensive to construct animations. This has led to an increase in the number, variety and complexity of animations produced. One of the areas that animations have been successfully applied is map anima- tions. Map animations have been studied by various disciplines such as computer sciences, remote sensing and pattern recog- nition. Most of the applications are central (i.e. desktop) in which data and services are physically located in the same machine and the analyses are carried out in the same place. Among these studies, [8] studies extracting the spatial pattern in time by visualization as an animation, [9] and [10] present the tech- nical aspects of the animated maps such as challenges and efficiency issues, [11] and [12] present their case studies with spatiotemporal phenomena. These early works are on recogni- tion of temporal changes in spatial datasets through animation, but our focus is creating animating web services enabling shar- ing and collaboration of animated spatial data among the virtual organizations through the distributed systems. Distributed Map Animation Services for Spatiotemporal Datasets A. Sayar