High Performance, Federated, Service-Oriented Geographic Information Systems Ahmet Sayar Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Doctor of Philosophy in the Department of Computer Science, Indiana University February 2009 Accepted by the Graduate Faculty, Indiana University, in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Doctoral Committee ________________________________ Prof. Geoffrey C. Fox (Principal Advisor) ________________________________ Prof. Randall Bramley ________________________________ Prof. Kay Connelly ________________________________ Prof. Yuqing (Melanie) Wu February 2, 2009 ii © 2009 AHMET SAYAR ALL RIGHTS RESERVED iii Acknowledgements This dissertation has been achieved with the encouragement, support, and assistance I received from many remarkable people. I would like to offer my sincere gratitude to them. First of all, I would like to thank my advisor Prof. Geoffrey C. Fox for his support, guidance and an exceptional research environment provided by him along the way of this endeavor. I deeply appreciate how much he contributed with his keen insight and extensive experience. His advice was always invaluable contribution to my academic life. I would also like to thank the members of the research committee for generously offering time, support, guidance and good will throughout the preparation and review of this dissertation. I am very thankful to Prof. Randall Bramley for his suggestions and remarkable inspiration, Prof. Kay Connelly and Prof. Yuqing (Melanie) Wu for their constructive comments, kindnesses and keen intellects. I want to thank all members of Community Grids Lab for the priceless moments that we shared together. I have had great pleasure of working with these wonderful people. I particularly thank Dr. Marlon Pierce for his supports and productive discussions on various aspects of my research. Finally, I am especially grateful to my family and friends for their contributions throughout my graduate studies. I have received wonderful support from my daughter iv Ayse Nazli, my parents, Mehmet and Semiha, my sisters, Selma, Zeynep and Hatice. Their constant love and encouragement were invaluable. Their belief and generosity are most profoundly acknowledged here. v Abstract Geographic information is critical for many earth related geo-science applications such as building disaster planning, crisis management, early-warning systems and urban planning. Decision making in Geographic Information Systems (GIS) increasingly relies on analyses of spatial data in map-based formats. Maps are complex structures composed of layers created from distributed heterogeneous data belonging to the separate organizations. This thesis presents a distributed service architecture for managing the production of knowledge from distributed collections of archived observations and simulation data through integrated data-views. Integrated views are defined by a federation service (“federator”) located on top of the standard service components. Common GIS standards enable the construction of this system. However, compliance requirements for interoperability, such as XML-encoded data and domain specific data characteristics, have costs and performance overhead. We investigate issues of combining standard compliance with performance. Although our framework is designed for GIS, we extend the principles and requirements to general science domains and discuss how these may be applied. vi TABLE OF CONTENTS CHAPTER 1 INTRODUCTION .................................................................................. 1 1.1. Motivation ............................................................................................................ 2 1.2. Why Federation .................................................................................................... 4 1.3. Research Issues .................................................................................................... 7 1.4. Organization of Dissertation .............................................................................. 11 CHAPTER 2 LITERATURE SURVEY .................................................................... 13 2.1. Background ........................................................................................................ 13 2.1.1. Geographic Information Systems (GIS) ..................................................... 13 2.1.2. Open GIS Standards and GIS Web Services .............................................. 16 2.2. Related Works .................................................................................................... 20 2.2.1. Linked Environments for Atmospheric Discovery (LEAD) ....................... 20 2.2.2. Geosciences Network (GEON) ................................................................... 21 2.2.3. Laboratory for Advanced Information Technology and Standards (LAITS): 22 CHAPTER 3 GIS WEB SERVICE DATA-GRID COMPONENTS ......................... 25 3.1. Geo-data and Common Data Models ................................................................. 26 3.2. Web Service Extensions to Standard Service Definitions ................................. 29 3.3. System Framework and Web-Service Components ........................................... 32 3.3.1. Web Feature Service ................................................................................... 33 3.3.2. Web Map Service ........................................................................................ 38 3.3.2.1. GetCapabilities Services....................................................................... 39 3.3.2.2. GetMap Services .................................................................................. 41 3.3.2.3. GetFeatureInfo Services ....................................................................... 47 3.3.3. Browser event-based Interactive Map Client Tools.................................... 53 3.3.3.1. Integration of AJAX approach to GIS Web Service Invocations ........ 59 3.3.3.2. AJAX & Web Services Synchronization Framework .......................... 61 3.3.3.3. A Use Case Scenario: Overlaying OGC‟s Maps with Google Maps ... 65 vii CHAPTER 4 FINE-GRAINED FEDERATION OF GIS WEB-SERVICE COMPONENTS ................................................................................... 68 4.1. Geo-Data and integrated data views................................................................... 70 4.1.1. Hierarchical Data Definition and Multi-layer Maps ........................................ 74 4.2. Federation Framework ........................................................................................... 75 4.3. Service Federation through Capability Aggregation .............................................. 79 4.3.1. Extending WMS as a Federator Service .......................................................... 80 4.3.1.1. Federating through Context Document:.................................................... 81 4.3.1.2. Federating through Aggregated WMS capability ..................................... 83 CHAPTER 5 APPLICATIONS OF THE FEDERATION FRAMEWORK.............. 88 5.1. The National Infrastructure Simulation and Analysis Center (NISAC) ............ 89 5.2. Pattern Informatics (PI), Earthquake Science .................................................... 96 5.3. Virtual California (VC), Earthquake Science .................................................. 103 CHAPTER 6 HIGH-PERFORMANCE SUPPORT IN INTEROPERABLE GEO- DATA RENDERING ......................................................................... 108 6.1. General Performance Issues ............................................................................. 109 6.1.1. Distributed Nature of Data ........................................................................ 109 6.1.2. Interoperability Cost – Common Data Model .......................................... 110 6.1.3. Tough Data Characteristics ....................................................................... 111 6.2. Extending OGC Standards with Streaming Data Transfer Capabilities .......... 112 6.3. Application of Pull Technique for GML Parsing and Rendering .................... 118 6.4. Adaptive load-balancing and Parallel Query Optimization ............................. 122 6.4.1. Problem Definition.................................................................................... 124 6.4.2. Workload Estimation Table for Two-dim Range Queries ........................ 125 6.4.3. Utilizing WT for Range Query Optimization ........................................... 130 6.4.4. Performance Evaluation ............................................................................ 134 6.5. Just-in-time Map Rendering ............................................................................. 139 6.6. Overall System Evaluation ............................................................................... 143 6.6.1. Data and Process Flow .............................................................................. 143 6.6.2. Test Case Scenario .................................................................................... 145 viii 6.6.3. Base-line System Test ............................................................................... 147 6.6.4. Performance Enhancement with Federation and Parallel Query Optimization through WT tables ............................................................................. 149 CHAPTER 7 ABSTRACTION OF THE FRAMEWORK FOR THE GENERAL DOMAINS