Presentation is loading. Please wait.

Presentation is loading. Please wait.

Conflation with JCS Automated and Human-Assisted Conflation Using the JCS Conflation Suite Presented at GeoTec 2003 Vancouver, BC Martin Davis, Technical.

Similar presentations


Presentation on theme: "Conflation with JCS Automated and Human-Assisted Conflation Using the JCS Conflation Suite Presented at GeoTec 2003 Vancouver, BC Martin Davis, Technical."— Presentation transcript:

1 Conflation with JCS Automated and Human-Assisted Conflation Using the JCS Conflation Suite Presented at GeoTec 2003 Vancouver, BC Martin Davis, Technical Architect

2 Conflation with JCS Overview of Conflation “Conflation” is a very broad term Conflation problems need to be precisely defined in order to be automated Conflation algorithms difficult to generalize Still awaiting “Grand Unifying Theory” of conflation

3 Conflation with JCS Overview of Conflation Terminology Matching – identifying features or data elements which represent the same real-world entity Alignment – whether two features or data elements have coincident geometry Adjustment – altering geometry or attributes of matched features to make them align Reference –dataset to be conflated to  (usually of greater spatial accuracy) Subject – dataset to be matched or adjusted

4 Conflation with JCS Overview of Conflation Problem Categorization Horizontal – conflation between adjacent datasets  e.g. Boundary Alignment Vertical – conflation between datasets covering the same area  e.g. Coverage Alignment, Road Network Matching Internal – conflation between items in a single dataset  e.g. Coverage Cleaning

5 Conflation with JCS Overview of Conflation Automated VS Human-Assisted Automated  uses algorithm(s) to match and adjust features automatically.  May not be able to fix 100% of problems Human-Assisted  use manual editing tools to adjust features  Assisted by automated tools to detect problems, perform precise adjustment

6 Conflation with JCS Overview of Conflation Workflow Acquire Datasets Data Preparation & Validation (QA) Problem Detection and Visualization Automated Conflation Human-assisted Conflation (if necessary) Persist Updated Data

7 Conflation with JCS The JCS Conflation Suite Project Project sponsor:  Dr. Mark Sondheim - Base Mapping and Geomatic Services Branch, MSRM With support from:  GeoConnections  Ministry of Sustainable Resource Management, Province of BC Project Timeline  Initiated: March 2002  Finish: ~March 2003

8 Conflation with JCS The JCS Conflation Suite Goals:  Address real-world conflation problems  Leverage existing spatial tools and modern software development techniques  Open development philosophy  Build toolbox for performing conflation JCS written in 100% pure Java JCS is Open Source (GPL license)

9 Conflation with JCS JCS Architecture JCS provides:  API  GUI Built using:  Java Topology Suite (JTS)  Unified Mapping Platform (JUMP)

10 Conflation with JCS JTS Topology Suite Implementation of OpenGIS Consortium Simple Features Specification Open-Source, 100% Java Goals:  Fast, production quality  Robust  Explicit precision model

11 Conflation with JCS JTS Topology Suite Geometry Model and Operations Geometry model: Points, LineStrings, Polygons, collections Spatial predicates (using Dimensionally Extended 9-Intersection Model) Boolean operations, buffer, convex hull, centroid, etc.

12 Conflation with JCS JUMP Unified Mapping Platform 100% pure Java Open Source (GPL license) Both API and GUI Goals:  Rich GUI environment for developing spatial algorithms, visualizing data and output  Interactive environment for supporting human-assisted spatial processes  Leverage capabilities of Java platform for spatial processing  Easily extensible

13 Conflation with JCS JUMP - API Features with attributes and geometry Feature Collections Spatial Access Methods  Quadtree, STR-Tree, Binary Interval Tree Warping  Affine Transform  Bilateral Interpolated Triangulation Dataset I/O  Well Known Text, GML, ESRI Shapefile

14 Conflation with JCS JUMP Workbench Multi-Window GUI Supports multiple layers of spatial data; rich styling options Provides GUI for JUMP API functions Geometry & Attribute editing Easily extensible via Plugin framework

15 Conflation with JCS Conflation in JCS Overview Provides tools for:  Dataset QA  Problem detection  Automated Conflation  Human-assisted conflation (manual edits) Kinds of conflation algorithms  Coverage Alignment  Road Network Matching

16 Conflation with JCS Coverage Alignment Problem Subtypes Boundary Alignment  e.g. Municipal Parcels  “Horizontal Conflation” Coverage Cleaning  “Internal Conflation” General Coverage Alignment  e.g. aligning suburb boundaries to parcels  “Vertical Conflation”

17 Conflation with JCS Coverage Alignment Algorithm Key idea: Lines that are “close” should be identical Match Line segments  Hausdorff distance < tolerance  Relative angle < tolerance Adjust Vertices  Snap close vertices  Add or merge vertices if necessary Heuristics:  Do not break topology  Minimize change to existing vertices

18 Conflation with JCS Coverage Cleaning Error Detection

19 Conflation with JCS Coverage Cleaning Automated Alignment

20 Conflation with JCS Coverage Cleaning QA of Automated Process

21 Conflation with JCS Coverage Cleaning Manual Tools – Vertex Snapping

22 Conflation with JCS Boundary Alignment Error Detection

23 Conflation with JCS Boundary Alignment Automated Conflation

24 Conflation with JCS General Coverage Alignment Error Detection

25 Conflation with JCS General Coverage Alignment Automated Conflation

26 Conflation with JCS Road Network Matching Problem Example

27 Conflation with JCS Road Network Matching Algorithm Match Nodes and Edges based on weighting Node Match weight  Distance between nodes  Topology match between incident edges Edge Match weight  Hausdorff distance between edges  Relative length of edges  For “straight edges”, relative angle

28 Conflation with JCS Road Network Matching Matching & Visualization

29 Conflation with JCS Road Network Matching Warping based on Matching

30 Conflation with JCS Further Development New / improved conflation algorithms  Complete Road Network Matching tools  Improve Coverage Alignment algorithm  Alignment to natural boundaries  E.g. Admin Boundary / Heights-of-land  Stream Network matching ( Refractions Research ) Additional JUMP functionality  Colour-theming by attribute  More flexible GML support JTS improvements  Robustness of spatial functions, buffer


Download ppt "Conflation with JCS Automated and Human-Assisted Conflation Using the JCS Conflation Suite Presented at GeoTec 2003 Vancouver, BC Martin Davis, Technical."

Similar presentations


Ads by Google