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Laser-Scan and GML
• UK company - member of the Yeoman Group– in digital mapping since 1974
• Long-time members of OpenGIS consortium– Provided primary author of GML-1 spec (AC)– Took part in WMT1 and 2, OWS1.1, 1.2
• Implemented SOTF to prototype next generation GML with Change-Only Update and topology
• Primary supplier of spatial technology to OSGB who are using GML as basis of new MasterMap
• Contributing topology expertise to GML-3
LSL Approach to Relay
• Now using 3rd party tools– to let us focus on our key technologies
• Emphasis of this demo is on– interoperability– topological structure
• Looking forward to GML-3
Topology
• Mathematical concept of spatial structure: “Characteristics of geometry which do not change when the coordinate space is deformed”
• Express explicit geometric relationships– connects to, touches, adjacent to, within
• Topology Primitives– Node, Edge, Face, Solid
• Should be present in most GIS data– Shared edges between land polygons– connected networks of roads
Radius Topology
• Enterprises and agencies want to hold business and spatial data in one database
• Radius Topology is the server-side topology manager for Oracle9i
• Enhances spatial data quality and query performance.
• Calculates and stores the topology in tables, using standard ISO 19107 model.
• Based on proven topology engine from Laser-Scan Gothic object database and toolkit
Today’s LSL Relay
RadiusTables
RadiusTriggers
RadiusTopology
Engine
Businessdata
Spatialdata
Oracle9i
SQL
OC
I
IntergraphGeoMedia
SnowflakeGo Loader
GMLGML MapInfo
Face Encoding
<gml:Face id="f1">
<gml:posEdge xlink:href="#e1"/>
<gml:posEdge xlink:href="#e2"/>
<gml:negEdge xlink:href="#e2"/>
<gml:posEdge xlink:href="#e3"/>
<gml:negEdge xlink:href="#e3"/>
<gml:isolated xlink:href="#n3"/>
</gml:Face>
Face records all adjacency and containment through encoding for boundary and isolated
GML 2.0 and 3.0 Geometry
• GML 2.0 provides for:– Simple geometry types
• Point/MultiPoint• LineString/MultiLineString• Polygon/MultiPolygon
– Boundary Types• LinearRing
– Simple linear interpolation
– Coordinates up to 3D
• GML 3.0 geometry– from ISO 19107– superset of GML 2.0– Geometric primitives up
to 3D volumetric solids– composites (line/arc)– splines, conics, tins– curves and surfaces.
• Topology model
Spatial Query Performance“Find all districts which touch or are covered by the county of Cambridgeshire (UK)”
Spatial Query Comparison
0.048 0.22
91
0102030405060708090
100
Oracle Spatial Oracle SpatialOptimised
Radius Topologyinside
Oracle Spatial
Features found per second
At Least 400 times faster !