1. Use of Conflation Software in US Census Bureau's TIGER Coordinate Correction Process Prepared for ESRI User Conference 2003 Prepared by Bernard Catalinotto Geo-Information Services, JV Alexandria, VA July 10, 2003

2. Conflation Tools in TIGER Correction Process Overview Background What is Conflation? What is MapMerger? Standard Approach Creative Approach Results & Next Steps

3. 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

4. Task 4/Geo-Serv Project Coordinate Correction Process 1. Data Preparation (Local File) 2. Coordinate Correction 3. Geo-Serv QC & Final Fix 4. Census QC 5. Upload into TIGER DB

5. 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

6. 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”)

7. 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

8. Conflation using MapMerger 1. Node match 2. Line match 3. Transfer attributes  Creates conflated data set

9. 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

10. MapMerger -- NODE MATCH – Automatic Results

11. MapMerger – LINE MATCH -- Automatic Results

12. MapMerger Manually Edit Line Match Results

13. 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 match 3. QC/fix in MapMerger Run Census/Geo-Serv/Custom QC programs Fix errors, rerun conflation in MapMerger After MapMerger Minor QC/fix; prepare deliverables

14. 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