Oracle8i Spatial Concepts

Concepts Geometric data types Oracle8i Spatial data model Spatial Layers Spatial query model Spatial indexing «Window» queries and «join» queries Geometric data types Oracle8i Spatial data model Spatial Layers Spatial query model Spatial indexing «Window» queries and «join» queries

Types of Spatial Data GIS (mapping) data CAM data CAD data

Geometric Types Points (X1, Y1, [Z1]) Line Strings (X1, Y1, [Z1],...Xn, Yn, [Zn]) –self-crossing lines are supported –lines that close to form a ring have no implied interior –straight, curved or mixed (compound) shapes Points (X1, Y1, [Z1]) Line Strings (X1, Y1, [Z1],...Xn, Yn, [Zn]) –self-crossing lines are supported –lines that close to form a ring have no implied interior –straight, curved or mixed (compound) shapes

Geometric Types (cont.) Polygons (X1, Y1, [Z1],... Xn, Yn, [Zn]) –polygons are rotation independent; outer rings must be counter clockwise, inner rings (voids) must be clockwise. –coordinates must close and interior is implied –interior area can be voided using additional elements (polygon with hole) –self-crossing polygons are not supported –straight, curved or mixed (compound) shapes Polygons (X1, Y1, [Z1],... Xn, Yn, [Zn]) –polygons are rotation independent; outer rings must be counter clockwise, inner rings (voids) must be clockwise. –coordinates must close and interior is implied –interior area can be voided using additional elements (polygon with hole) –self-crossing polygons are not supported –straight, curved or mixed (compound) shapes

Geometric Types Point Polygon Polygon with hole Self-crossing line strings Valid Self-crossing polygons Not valid Not valid Line string Arc line string Compound line string Compoundpolygon Optimizedpolygons

Geometric Representations Spatial attribute of a spatial feature: geometric representation of its shape in some coordinate space Called geometry Oracle Spatial Object-Relational model represents geometries using tables with a single column of type MDSYS.SDO_GEOMETRY and a single row per geometry instance Relational model: table with a predefined set of columns of type NUMBER and one or more rows for each geometry instance Spatial attribute of a spatial feature: geometric representation of its shape in some coordinate space Called geometry Oracle Spatial Object-Relational model represents geometries using tables with a single column of type MDSYS.SDO_GEOMETRY and a single row per geometry instance Relational model: table with a predefined set of columns of type NUMBER and one or more rows for each geometry instance

Spatial Data Model PointLinePolygon Elements Geometries Spatial layer

Elements Element 1 Element 2 Element 3 Element 4 Element 5 Element 6 Element 7 Basic building block of a geometry Element types –Point –Line –Polygon Constructed using coordinates Limit on number of coordinates Hawaii, USA

Geometry 1 California Geometry 2 Texas Geometry 3 Florida Geometry 4 Hawaii Geometry Represents a spatial feature Consists of an ordered set of primitive elements Represents a spatial feature Consists of an ordered set of primitive elements

Layers Consist of geometries that share a common set of attributes A layer is a geometry column in a table Consist of geometries that share a common set of attributes A layer is a geometry column in a table States layer