GIS und relationale Datenbanken: Arc/Info SDE und Oracle 8i Spatial Schedule: Timing Topic 60 minutes Lecture 30 minutes Practice 90 minutes Total

Übersicht Relationale Datenbanken Grenzen von Relationalen Datenbanken Oracle 8i Spatial ArcSDE

RDBMS Relationale Datenbanken Managment Systeme Alle Informationen werden in Tabellen gespeichert In jedem Feld befindet sich eine (atomare) Information Jeder Datensatz wird mit einem eindeutigen Schlüssel (Primary Key) versehen (z.B. ID) Beziehungen zwischen Datensätzen werden über Fremdschlüssel realisiert Indizierung von Feldern zur Steigerung der Geschwindigkeit bei der Datensatzsuche Abfragesprache SQL (Structured Query Language)

RDBMS Relationale Datenbanken Managment Systeme Primärschlüssel Fremdschlüssel

Grenzen von RDBMS Keine komplexen Objekte in Feldern Komplexe Objekte müssen auf mehrere Spalten oder gar Relationen verteilt werden Alle Operationen basieren auf Tabellenstruktur Es sind keine direkten Operationen mit Objekten möglich Beispiel GIS: Körper Flächen Knoten Kanten

Bisherige GIS-Systeme Getrennte Speicherung von Geometrie und Sachdaten Sachdaten/Topologie in Shapefiles Geometrie/Attribute in RDBMS Gründe: Mangel an OO-DBMS Performance (räumliche Indizes) Geometrie in BLOB-Feldern Keine Datenbankoperationen mit Blob-Feldern möglich GIS-System ist für die Arbeit mit diesen Daten notwendig

Neue GIS-Systeme Ideale Lösung Kommerzielle Systeme Oracle 8i Eine Datenbank für alle Daten Kommerzielle Systeme Oracle 8i Spatial Esri ArcSDE IBM DB2 Spatial Extender Informix Spatial DataBlade Oracle 8i Keine Größenbegrenzung (mehrere Terrabyte möglich) Automatische Aufteilung auf Teildatenbanken z.B. nach Staaten, Regionen oder anderen Kriterien Orientiert sich weitestgehend an OGC SQL Spezifikationen

Oracle 8i - Primitive Geometrie Typen ® Oracle 8i - Primitive Geometrie Typen Self-crossing line strings Zulässig Arc line string Compound line string Point Line string Self-crossing polygons Nicht zulässig Polygon with hole Polygon Compound polygon Optimized polygons Supported Geometric Types Oracle Spatial supports three multi-dimensional geometric primitive types and geometries composed of collections of these types. The three primitive types are: Points (X1, Y1) Line strings (X1, Y1, Xn, Yn) Polygons (X1, Y1,... Xn, Yn) Points are elements composed of between two and four ordinates, if only X and Y - often correspond to longitude and latitude. Line strings are composed of two or more pairs of points that define line segments. Self-crossing lines are supported. Lines that cross to form a ring have no implied interior. Coordinates may be stored in clockwise or counterclockwise order. Polygons are composed of line strings that form a closed ring, and the interior of the polygon is implied. Polygons may also contain holes which are constructed by defining inner polygons. Holes represent polygon voids (doughnuts). Self-crossing polygons are not supported although self-crossing line strings are. If a line string crosses itself, it does not become a polygon. A self-crossing line string does not have any implied interior. Polygon can be exterior polygons or interior polygons (also called holes). An exterior polygon has to be followed by its interior polygons. Exterior polygons must be stored in counter clockwise rotation. Interior polygons must be stored in clockwise rotation. circle rectangle

Oracle 8i - Erstellung von Objekten ® Oracle 8i - Erstellung von Objekten SQL> INSERT INTO LINES VALUES ( 2> attribute_1, …. attribute_n, 3> MDSYS.SDO_GEOMETRY ( 4> 2002, null, null, 5> MDSYS.SDO_ELEM_INFO_ARRAY (1,2,1), 6> MDSYS.SDO_ORDINATE_ARRAY ( 7> 10,10, 20,25, 30,10, 40,10)) 8> ); (20,25) (10,10) (30,10) (40,10)

Shapefile → Oracle 8i - Converter ® Shapefile → Oracle 8i - Converter Verwendet den Oracle „SQL*Loader“ Verarbeitet Attribute (.DBF) ebenso wie Geometrie (.SHP and .SHX) Erstellt ein SQL-Skript zur Generierung einer Spatial-Tabelle Unterteilt große Daten automatisch in vom „SQL-Loader“ verarbeitbare SQL-Scripts Wird nicht offiziell unterstützt

Spatial Indizierung Basiert auf „Quad Tree Decomposition“ ® Spatial Indizierung Basiert auf „Quad Tree Decomposition“ Indiziert Punkte, Linien und Polygone Zwei unterschiedliche Methoden Fixed tiling Hybrid tiling Der Vorgang der Indizierung nennt sicht „tessellation“ (Überlappungsfreie und vollständige Abdeckung des Raumes) Die Ergebnisse eines Tessellation-Prozesses werden in einem „spatial index“ gespeichert Indexing Geometric Features Using a Spatial Index Once data has been loaded into spatial tables through either bulk or transactional loading, a spatial index needs to be generated or updated for efficient access to the data. Spatial Cartridge provides two methods, fixed and hybrid tiles, for use in spatial indexing. The fixed-sized method is the recommended method, while, the hybrid method is included in the 7.3.4 and 8.0.4 releases as experimental. The process of determining which tiles cover a given geometry is called “tessellation.” The results of the tessellation process are stored in the layer_SDOINDEX table. The SDOINDEX tables are to be considered index-only tables and should not be manipulated by any method other than the provided procedures. The tessellation process is executed through one of the following four procedures: POPULATE_INDEX POPULATE_INDEX_FIXED UPDATE_INDEX UPDATE_INDEX_FIXED These four procedures are defined later in this section. If the data has been loaded through the bulk load utility, you can call the POPULATE_INDEX or POPULATE_INDEX_FIXED procedure once to tessellate all geometric features in the layer and add the generated tiles to the spatial index table. If data is updated or deleted for a specific geometry, UPDATE_INDEX or UPDATE_INDEX_FIXED can be called to update the index for a designated geometry.

Quad Tree - Tessellation Fixed Tile Decomposition Hybrid Tile Decomposition Fixed-size indexing is recommended and has the following characteristics: Selectivity of the primary filter is less than variable tiling Good selectivity Better performance Example: 50 records/second Variable-size indexing is not recommended but has the following characteristics: Selectivity of primary filter is better (but slower in the long run) Better selectivity Good performance Example: 35 records/4 seconds Instructor Note This slide has a build for each decomposition.

® Oracle 8i – Auffinden von Objekten Datenbank nach „Fixed Tiling Tesselation“ T1 T2 T7 T3 T4 T5 T6 T8 T9

Oracle 8i – Auffinden von Objekten 1. Filterschritt: Grobfilterung ® Oracle 8i – Auffinden von Objekten 1. Filterschritt: Grobfilterung T1 T2 T7 T3 T4 T5 T6 T8 T9

Oracle 8i – Auffinden von Objekten 2. Filterschritt: exakte Filterung ® Oracle 8i – Auffinden von Objekten 2. Filterschritt: exakte Filterung T1 T2 T7 T3 T4 T5 T6 T8 T9

Egenhoefer 4-Schnittmodell A B A B 1 1

Egenhoefer 9-Schnittmodell A B A B 1 1

Oracle 8i - Topologische Relationen ® Oracle 8i - Topologische Relationen B A A A B B Contains Inside Covers Covered by Touch A A A B B B Overlap Boundaries Intersect Overlap Boundaries Disjoint Equal A B Disjoint

Oracle 8i – Beispiele für Buffering ® Oracle 8i – Beispiele für Buffering Einfache Geometrietypen Gruppen von Geometrietypen

® Oracle 8i – Beispiel Suche alle Städte in einem Bereich um Highway I 170 select c.city from cities c, interstates i where highway = 'I 170' and mdsys.sdo_relate ( c.location, mdsys.sdo_geom.sdo_buffer ( i.geom, 0.5, 0.00000005), 'mask=ANYINTERACT querytype=WINDOW' ) = 'TRUE';

ArcSDE – Universelle Datenschnittstelle Server für den Zugriff auf Geo-Daten (über Dienste) Zugriff auf die Daten übers Netzwerk / Internet Erleichtert den Übergang zu RDBMS 2 Module SDE Server for Coverages SDE Server for DBMS

ArcSDE – Universelle Datenschnittstelle Zugriff auf die Daten in Tabellenform mit komplexen Objekten in Feldern Programmierschnittstelle (C, C++, VisualBasic, ...) Zugriff auf Daten aus verschiedensten Systemen (ArcInfo, ArcView, IMS, AutoCad, MicroStation, ...)

ArcSDE Server for Coverages Nutzt die ArcInfo Datenformate Es ist keine Konvertierung notwendig

ArcSDE Server for DBMS Speichert die Daten in üblichen RDBMS (wie z.b Oracle, IBM DB2, Informix, MS SQL-Server, Sybase usw.) Nutzt eventuell vorhandene Spatial-Funktionen der Datenbanken Oracle 8i Spatial IBM DB2 Spatial Extender Informix Spatial DataBlade

Ende

Oracle 8i – OGC Spezifikationen Point Point Cluster Multipoint Curve Circle Optimized Rectangle LineString LineString, Line, Linear Ring Arc Strings MultiCurve Compound Line String MultiLineString Surface Polygon ArcPolygon MultiSurface Compound Polygon MultiPolygon Supported Geometric Types Oracle Spatial supports three multi-dimensional geometric primitive types and geometries composed of collections of these types. The three primitive types are: Points (X1, Y1) Line strings (X1, Y1, Xn, Yn) Polygons (X1, Y1,... Xn, Yn) Points are elements composed of between two and four ordinates, if only X and Y - often correspond to longitude and latitude. Line strings are composed of two or more pairs of points that define line segments. Self-crossing lines are supported. Lines that cross to form a ring have no implied interior. Coordinates may be stored in clockwise or counterclockwise order. Polygons are composed of line strings that form a closed ring, and the interior of the polygon is implied. Polygons may also contain holes which are constructed by defining inner polygons. Holes represent polygon voids (doughnuts). Self-crossing polygons are not supported although self-crossing line strings are. If a line string crosses itself, it does not become a polygon. A self-crossing line string does not have any implied interior. Polygon can be exterior polygons or interior polygons (also called holes). An exterior polygon has to be followed by its interior polygons. Exterior polygons must be stored in counter clockwise rotation. Interior polygons must be stored in clockwise rotation.