1SQL/SDA: A Query Language for SQL/SDA: A Query Language for Supporting Spatial Data Analysis and Supporting Spatial Data Analysis and Its WebIts Web--Based ImplementationBased ImplementationGroup MemberGroup MemberShan HuangShan HuangJisuJisu ohohTopics:Topics:•• MotivationMotivation•• Problem StatementProblem Statement•• Major ContributionMajor Contribution•• Key ConceptKey Concept•• Validation MethodologyValidation Methodology•• Assumption Assumption2MotivationMotivation•• Limited GISLimited GIS--based decisionbased decision--making Spatial making Spatial analysis functionsanalysis functions–– no effective interface to support user requestno effective interface to support user request•• Current spatial query language (Spatially Current spatial query language (Spatially Extended Extended SQLsSQLs))–– Representation of spatial dataRepresentation of spatial data–– Management of spatial dataManagement of spatial data•• Complexity of current GISComplexity of current GIS--softwaresoftwareMotivation (contd.)Motivation (contd.)•• Find a land parcels Find a land parcels suitable for growing suitable for growing coffee in Jamaica.coffee in Jamaica.–– Evaluation criteria Evaluation criteria temperature, altitudes, temperature, altitudes, area >1000, etc.area >1000, etc.3Problem StatementProblem Statement•• GivenGiven–– Spatial Data TypeSpatial Data Type–– Spatial Data Analysis FunctionSpatial Data Analysis Function•• FindFind–– SQL/SDASQL/SDA–– WebWeb--based Interface for Spatial Data Analysisbased Interface for Spatial Data Analysis•• ConstrainsConstrains–– Relational DatabaseRelational Database–– SQL with Geometry TypesSQL with Geometry Types•• ObjectiveObjective–– Easy to useEasy to use–– EfficientEfficientMajor ContributionMajor Contribution•• SQL/SDASQL/SDA–– Restructuring the FROM ClauseRestructuring the FROM Clause•• Visual Interface and Hybrid ModelVisual Interface and Hybrid Model–– Takes advantage of the Web GIS Design in Takes advantage of the Web GIS Design in Client/Server EnvironmentClient/Server Environment•• Client Client –– provides a query interfaceprovides a query interface•• Server Server –– carry out query processing on spatial databasescarry out query processing on spatial databases•• Compliance with Compliance with –– Current GIS PackagesCurrent GIS Packages–– SQL StandardSQL Standard4Key ConceptsKey Concepts•• Spatial FeatureSpatial Feature–– Spatial attributes (e.g., coordinates and topological Spatial attributes (e.g., coordinates and topological relationships)relationships)–– NonNon--Spatial attributes (e.g., name and size)Spatial attributes (e.g., name and size)•• Spatial Data TypeSpatial Data Type–– Geometry: Point, Geometry: Point, LinestringLinestring, Polygon, Collection, Polygon, Collection•• Collection: Multipoint, Collection: Multipoint, MultilinestringMultilinestring, , MultipolygonMultipolygon•• Structure and Syntax of SQL/SDAStructure and Syntax of SQL/SDA–– Align with the SQL design conceptAlign with the SQL design concept•• SELECT SELECT -- projectionprojection•• FROMFROM -- Cartesian productCartesian product•• WHERE WHERE -- selection selection Key Concepts (contd.)Key Concepts (contd.)•• Spatial Analysis FunctionsSpatial Analysis FunctionsCreate a new set of Create a new set of spatial features spatial features Calculate distance and Calculate distance and directiondirectionTest spatial Test spatial relationshipsrelationshipsAccess properties of Access properties of spatial featuresspatial featuresPurposePurposeINTERSECTION, UNION, BUFFERINTERSECTION, UNION, BUFFERDerivation Derivation DISTANCE, DIRECTIONDISTANCE, DIRECTIONMetric Metric OVERLAP, DISJOINT, TOUCHOVERLAP, DISJOINT, TOUCHSpatial Spatial Relationship Relationship AREA, LENGTH, CENTROIDAREA, LENGTH, CENTROIDProperty Property ExampleExampleFunctionFunction5Key Concepts (contd.)Key Concepts (contd.)Example of SQL/SDA queryExample of SQL/SDA query•• Display the land parcels and their corresponding area on the Display the land parcels and their corresponding area on the condition that the condition that the landuselanduse type of each parcels brush land and soil type of each parcels brush land and soil type is ‘A’ and area is between 700 hectares to 900 hectarestype is ‘A’ and area is between 700 hectares to 900 hectareslanduse(IDlanduse(ID, Type, Location), Type, Location)soil (ID, type, Location)soil (ID, type, Location)SELECTSELECT lu.IDlu.ID, , sl.IDsl.ID, , ILocationILocation, , areavalareavalFROMFROM ( ( SELECTSELECT *, *, OVERLAP OVERLAP ( ( lu.Locationlu.Location, , sl.Locationsl.Location ) ) ASAS overlapvaloverlapval, , INTERSECTION INTERSECTION ( ( lu.location,sl.locationlu.location,sl.location ) ) ASAS iLocationiLocation,,AREAAREA ((iLocationiLocation) ) ASAS areavalareavalFROM FROM landuselanduse as as lulu, soil , soil ASAS slsl))WHEREWHERE lu.typelu.type = ‘= ‘BrushlandBrushland’ ’ ANDAND sl.typesl.type = ‘A’ = ‘A’ ANDAND overlapvaloverlapval= True = True ANDAND areavalareaval> 700> 700ANDAND areavalareaval< 900< 900Key Concepts (contd.)Key Concepts (contd.)•• SolutionSolutionFig.2. The Fig.2. The intermediate intermediate relation of the relation of the FROM clause in FROM clause in queryquery6Key Concepts (contd.)Key Concepts (contd.)•• Solution (contd.)Solution (contd.)Fig. 3. The result of queryFig. 3. The result of queryKey Concepts (contd.)Key Concepts (contd.)ImplementationImplementation of SQL/SDA on the Webof SQL/SDA on the WebClientClient•• provides query interfaceprovides query interfaceServer Server •• Query processor and Spatial Query processor and Spatial Database Engine (SDE)Database Engine (SDE)•• carry out query processingcarry out query processing7Validation MethodologyValidation Methodology•• Examples of SQL/SDA queriesExamples of SQL/SDA queries•• Case StudyCase Study–– Macro Languages of GISMacro Languages of GIS•• Difficult to learnDifficult to learn•• No optimization strategyNo optimization strategy–– Previous Spatially Extended Previous Spatially Extended SQLsSQLs (SESOL)(SESOL)•• spatial relationship and metric constrains, derivation functionsspatial relationship and metric constrains, derivation functionsare not accommodatedare not accommodated•• Spatial functions