Transcript GML Relay 2002

Netherlands GML Relay
TDN Emmen
Friday 13th December 2002
Paul Hardy
[email protected]
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
GML 2.0 in action
OS MasterMap
Ordnance
Survey
Crown
Copyright
Example of data
from GML in
LAMPS2
Data courtesy of
Topografische Diens
GML Relay 2002 Data
(Gothic LAMPS2)
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
GML Relay 2002 Data
(MapInfo/Oracle/Radius)
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
Shared Edges, Shared Nodes
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 LaserScan Gothic object database and toolkit
Today’s LSL Relay
MapInfo
GML
Snowflake
Go Loader
GML
Intergraph
GeoMedia
SQL
OCI
Radius
Topology
Engine
Radius
Tables
Radius
Triggers
Business
data
Spatial
data
Oracle9i
Go Loader
Radius Topology
Configuration Manager
Radius Topology
Classes and Priorities
Most GIS data is Spaghetti
gaps
slivers
undershoots
overshoots
… data faults affect query quality
Snapping and Topology
...or...
Rules: Node Formation
Share Node
Node Split Edge
Edge Split Edge
Priorities: Gold Standard Data
Before
After
- High priority feature
- Low priority feature
Face Topology - Containment
Need to find all features on the lake
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
GML 2.0 Geometry Schema
AS Topic 1/ISO 19107 Geometry
GML 2.0
GML-3 Topology
Edge
Edge
Spatial Query Performance
“Find all districts which touch or are covered by the
county of Cambridgeshire (UK)”
Spatial Query Comparison
100
90
80
Features 70
found
60
per
50
second
40
30
20
10
0
91
0.048
Oracle Spatial
At Least 400 times faster !
0.22
Oracle Spatial
Optimised
Radius Topology
inside
Oracle Spatial
Error in Topology
Edges & Nodes
Edit of Edge modifies both polygons
Edges & Nodes created dynamically
Export to GML via GeoMedia
Resultant XML (in MSIE)
Resultant XSD Schema
Round trip the exported GML
(with faulty projection!)
GML with Topology
Is The Way Ahead !
http://www.Laser-Scan.com
[email protected]