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A few Geometric Rules for Cross-border Data Merging

This document explores essential geometric rules necessary for the seamless interoperability of datasets within the Open Geospatial Initiative (OGC) for EU communities. It outlines four primary integration methods: Cartographic, Topological, Geo-semantic, and Graph integration. Each method emphasizes the importance of enforcing geometric relationships and applying semantic rules after ensuring the topological integrity of the data. Furthermore, it discusses the process of transforming coordinate systems and integrating terrains to create accurate and meaningful geographic data representations, crucial for cross-border collaboration.

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A few Geometric Rules for Cross-border Data Merging

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  1. Provision of interoperable datasets to open GI to EU communities A few Geometric Rulesfor Cross-border Data Merging R. Laurini February 2009

  2. Sets of Geometric Rules • 1 – Cartographic integration: maps look good • 2 – Topological integration: Eigenhofer relationships hold ==================================== • Only once those rules are enforced, semantic (ontology-based) rules can be applied ===================================== • 3 – Geo-semantic integration: artificially-cut objects are reconstituted • 4 – Graph integration: minimum path algorithm can run

  3. Coordinate integration X, Y X, Y Z Z Ellipsoid 1 Ellipsoid 2 If Referencings systems are different Then select a unique system And transform all points

  4. Zone A Zone A BA Zone B Zone B BB AFTER Boundary Force-Fitting Midline(BA,BB) BEFORE If Hausdorff Distance between BA and BB < epsilon Then BA and BB are both replaced by Midline(BA,BB)

  5. Zone A Zone A BA Zone B Zone B BB AFTER Topological IntegrationEigenhofer relation BEFORE If 2 zones are neighbouring and boundaries were force-fit Then Touches (ZoneA, ZoneB)

  6. Linear Extremity IntegrationRoads, Rivers, etc Zone A LA Zone A LA PA PB Midpoint(PA,PB) Zone B Zone B LB LB BEFORE AFTER If Euclidean Distance between PA and PB < epsilon Then PA and PB are replaced by Midpoint(PA,PB) And Touches (LA, LB)

  7. Zone A Zone B AFTER Geo-semantic integration: Reconstitution of artificially-cut objects Zone A OA O OB Zone B BB BEFORE If Type OA = Type OB And Hausdorff Distance between OA and OB < epsilon Then OA and OB are replaced by a single object O=OAOB

  8. Graph IntegrationRoads, Rivers, etc Zone A Zone A LA’  GraphA LA  GraphA Zone B Zone B LB’  GraphB LB  GraphB BEFORE AFTER If Type LA = Type LB And LA and LB were force-fit Then Graph = GraphAGraphB

  9. Integration of terrains Boundary of B Boundary of A Intermediary zone AFTER BEFORE IF Terrain models are different Then transform into triangles And fill the intermediary zones by additionnal triangles

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