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Prepared for ESRI User Conference 2003 Prepared by Bernard Catalinotto Geo-Information Services, JV Alexandria, VA July 10, 2003. Use of Conflation Software in US Census Bureau's TIGER Coordinate Correction Process. Conflation Tools in TIGER Correction Process Overview. Background - PowerPoint PPT Presentation
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Use of Conflation Softwarein US Census Bureau's TIGER
Coordinate Correction Process
Prepared for ESRI User Conference 2003
Prepared by Bernard CatalinottoGeo-Information Services, JV
Alexandria, VA
July 10, 2003
Conflation Tools in TIGER Correction Process
Overview
Background What is Conflation?
What is MapMerger?
Standard Approach Creative Approach Results & Next Steps
Initial and Major Programs
TIGER Coordinate Correction
Initial Programs Census R&D – 77 Counties Geo-Serv Contract – 190 Counties
Major Program MTAIP/Harris Corp – 3000+ Counties
Task 4/Geo-Serv Project
Coordinate Correction Process
1. Data Preparation (Local File)
2. Coordinate Correction3. Geo-Serv QC & Final Fix4. Census QC5. Upload into TIGER DB
Task 4/Geo-Serv Contract
Coordinate Correction Tasks
Step 1 Conflate TIGER to Local file Match all matchable features
Step 2 Find and Fix Flag issues, resolve, fix, flag action
Step 3 Prepare Deliverables Re-format Prepare QC Reports
Run QC programs Perform 100% Visual Check
What is Conflation? Combine 2+ files -- create RESULTS file
includes best aspects of each file
RESULTS file Source file attributes…..”Brains from TIGER” Target file graphics…….”Beauty from Local” Differences are resolved
Rubber-sheet unmatched source features (“Orphans”)
What is MapMerger?ArcMap extension for automated conflation
Automatic Match 70% to 95% of the features automatically
one-to-one matched
Match editing tools for manually editing the results of
automatic matching
Creates conflated data set
Conflation using MapMerger
1. Node match2. Line match3. Transfer attributes Creates conflated data set
Conflation - Vendor 1 (EarthData)
Standard Approach
Node match Match by layer 45 meters; visual check; fix errors 60 meters; visual check; fix errors
Line match Match; visual check; fix errors
MapMerger Goal 80-90% of all possible matches
MapMerger -- NODE MATCH – Automatic Results
MapMerger – LINE MATCH -- Automatic Results
MapMerger
Manually Edit Line Match Results
Conflation in MapMerger - Vendor 2 (Pixxures)
Creative Approach[Note: Skip Node match]
1. Start with Auto Line match 1 meters; check no errors 2 meters; check no errors Stop when encounter errors -- usually around 7
meters
2. Manual Line match3. QC/fix in MapMerger
Run Census/Geo-Serv/Custom QC programs Fix errors, rerun conflation in MapMerger
After MapMerger Minor QC/fix; prepare deliverables
Results & Next Steps
Results Efficient use of conflation software & ESRI
GIS technologies
Next Steps All three vendors making substantial
contributions to program success Goal: Complete 190 counties by 9/30/03