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New automated techniques to validate and populate property valuations

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  • 1. New Automated Techniques to Validate and Populate Property ValuationsInternational Property Tax Institute Commercial Properties Conference May 3 and May 4, 2012 Montego Bay, Jamaica Robert.Carroll@Pictometry.ca Pictometry Canada
  • 2. Overview  New challenges  Austere Budget: resources, manpower, fleet costs  Revenue Pressures  Inaccurate/Inefficient Legacy Procedures  Public Transparency  New opportunities
  • 3. Inefficient Procedures
  • 4. Transparency
  • 5. Accuracy Issues
  • 6. Opportunities• New standard of field review - IAAO 3.3.5• Desktop appraisal is now standard procedure• Pictometry is single-source supplier remote desktop appraisal data:  Metric georeferenced ortho, oblique, street- side imagery  ChangeFindr automatic building change detection  Sketch Check compares building sketch with geographic data  CAMA integration
  • 7. ChangeFindr – What is it? ChangeFindr is a building outline creation and analysis service providing automated change detection between two respective years of aerial imagery. The combined technology enables GIS professionals, real property tax agencies, planning departments, and public safety users to more easily compare changes in land and property features between existing county aerial photos and new imagery of the same area.
  • 8. Change Detection ……detects changes in an area that could go undetected, such as additions to existing structures, demolitions, land use changes, new construction, or other real property features. The process includes the ability to create GIS polygon “building outlines” and analyze them for changes in size and shape.
  • 9. Target of Services Residential, Commercial, and Industrial Buildings •Isolated Garages, Mobile Homes, Sheds •Greenhouses and Silos •Water Storage Tanks •Other features with a roof
  • 10. Not Target of Services Vehicles, Boats, Ships •Pools •Paved areas •Bare ground surrounded by a fence or wall •Steel Tower/Frames, Antenna, Cell phone towers •Billboards •Tombstones •Changes in the vertical direction (e.g. a one story building that is renovated to a two story building)
  • 11. Steps in the Process 1. Building Outline Creation (BOC) 3. Change Detection (CD)
  • 12. Building Outline Creation Base imagery Building outline
  • 13. Change Detection Example: Outlines are compared to historical imagery to update the outline file Building outline Latest imagery Updated Building outline
  • 14. Deliverable Products  Primary deliverable is a geospatial database of building outlines  Attributes of the deliverable include…  Parcel ID  X,Y coordinate of center of building polygon  Change Detection Classification – Existing, Changed, Destroyed, New, Possibly Changed
  • 15. Enhanced Features  Assigning Colors/Themes by status type  Regional Status Report  statistical results for the regions defined by the customer (e.g. townships, wards).  Lengths of the Building Sides  Table lists lengths of the sides of the buildings  Percentage of Change  Added columns to Building Outline table for “Orig_Area” and “ChangeRate”
  • 16. Sample Regional Report
  • 17. Displayed on ArcGIS
  • 18. Sample Length of Sides Table
  • 19. Deliverables-Samples Building outline
  • 20. Deliverables-Samples Tabular data
  • 21. Samples 2005 2007 Existing
  • 22. Samples 2005 2007 New
  • 23. Samples 2005 2007 Changed
  • 24. Samples 2005 2007 Possibly Changed
  • 25. Samples 2005 2007 Demolished
  • 26. Samples 2005 2007 Unknown
  • 27. Accuracy- Change Detection The process is better than 98% accurate •False Positive Rate: ratio of buildings with fault state for all Changed/New/Demolished buildings ≤ 2.0% •False Negative Rate: ratio of buildings with fault state for Existing buildings ≤ 0.2%
  • 28. Proven Return On Investment  Geauga County, Ohio  51,000 Parcels  2004 - $1.8 million in property value was found after reappraisal data collection was performed.  $35,000 in tax revenue on a $17,500 investment.  After a 2nd ChangFindr Project with new imagery the following was reported
  • 29. Geauga County ChangeFindr Results - 2004-2007 District $ Value Found $ Dest. Prop Net $ Value Assessed Value Tax rate Approx. Tax Amt Auburn $292,200 $1,700 $290,500 $101,675 0.059239558 $6,023 Bainbridge $156,100 $4,700 $151,400 $52,990 0.066361555 $3,516 Burton $336,400 $0 $336,400 $117,740 0.040108602 $4,722 Burton Village $32,400 $0 $32,400 $11,340 0.042306082 $480 Chardon Twp $130,200 $0 $130,200 $45,570 0.050454279 $2,299 Chardon City $44,300 $3,000 $41,300 $14,455 0.051471305 $744 Chester $602,400 $4,200 $598,200 $209,370 0.057045359 $11,944 Claridon $205,800 $0 $205,800 $72,030 0.040697997 $2,931 Aquilla Village $21,200 $0 $21,200 $7,420 0.052988997 $393 Hambden $323,200 $0 $323,200 $113,120 0.052204926 $5,905 Hunting Valley $0 $0 $0 $0 0.050284185 $0 Huntsburg $446,300 $3,000 $443,300 $155,155 0.04814363 $7,470 Middlefield $814,600 $6,000 $808,600 $283,010 0.046251006 $13,089 Middlefield Village $3,300 $0 $3,300 $1,155 0.045118574 $52 Montville $217,100 $0 $217,100 $75,985 0.041318239 $3,140 Munson $151,200 $1,200 $150,000 $52,500 0.052656419 $2,764 Newbury $569,900 $0 $569,900 $199,465 0.047635053 $9,502 Parkman $742,900 $4,800 $738,100 $258,335 0.045080778 $11,646 Russell $298,900 $33,300 $265,600 $92,960 0.056766935 $5,277 South Russell Village $31,200 $0 $31,200 $10,920 0.066651042 $728 Thompson $107,100 $0 $107,100 $37,485 0.04251769 $1,594 Troy $151,100 $0 $151,100 $52,885 0.043594487 $2,305 Total $5,677,800 $61,900 $5,615,900 $1,965,565 $96,526Provided by the Geauga County Auditors Office Tracy A. Jemison, AAS Auditor
  • 30. What is Pictometry Sketch Check?
  • 31. A Sketch Verification Solution Sketch Check Benefits • Quickly verify whether current sketches in CAMA system are correct • Reduce field visits and allocate staff resources more efficiently • Increase tax revenues by identifying previously undetected property changes • Convert sketches into geo- referenced shape file layer that can be used in GIS
  • 32. Sketch Check Target Market Primary Market: • Assessment / Appraisal • Target ChangeFindr customers & customers who have adopted IAAO standards Secondary Markets: • The geo-referenced building footprint shapefile layers have value for other departments such as Zoning, Planning and E911
  • 33. How Sketch Check Works• Sketches are extracted from CAMA• Sketch Vectors are: • Geo-referenced • Overlayed on ortho imagery • Rotated to best fit • Flagged / Categorized appropriately• Out of scope for Pictometry Sketch Check: • Sketch correction • Sketch creation
  • 34. Definition of Categories • Match – Sketch matches building • Minor Mismatch – Minor amount of the building’s outline does not match between the ortho & the sketch (~ 100 square feet or less*) • Major Mismatch – Significant amounts of the building’s outline does not match between the ortho & sketch (~ 100 square feet or more*) Match • No Bldg – No building appears in the ortho for the corresponding sketch • Undeterminable – Substantial amounts of the building outline cannot be determined from the ortho—typically due to tree cover • New Construction – New construction or additional building is in the ortho, but no sketch was provided—only indicated for parcels where a sketch already exists w/in the parcel • Unable to Geo-reference – Assigned to parcels that contain sketches for Major Mismatch which the vector data could not be processed or there were multiple nearly identical buildings on the same parcel (so sketches cannot be matched to buildings). This flag is only provided in the scoring table and associated shapefile. * As determined by visual comparison—not by actual measurementNew Construction /Additional Building
  • 35. Requirements Data• CAMA and Sketch system type• Sketch vector data in electronic format: • Preferable formats: Shapefile or Apex. • We cannot process image files such as JPG, PNG or IMG but there should be a digital sketch file used to make that image file in the CAMA system • For proprietary formats, Pictometry will work with sketch providing vendor to acquire converted data, which may require conversion fee• Parcel layer: Shapefile or comparable format that contains a unique identifier for each parcel• Ortho tiles • 12” GSD or better, RBG, projected, with world files • Acceptable formats: ECW, JPEG or TIFF• Ortho tile grid shapefile: shapefile that defines the ortho tile layout• Regional shapefile (Optional): For incremental delivery purposes (not reporting)
  • 36. Customer Deliverables • Shapefiles containing geo-referenced sketches as polygon feature classes - Each category - All file • Scoring Table (Excel & Shapefile format) • Summary Report • Customer DocumentationDetail on Reports
  • 37. Sketch Check vs. ChangeFindr • Pictometry Sketch Check & ChangeFindr help assessors improve productivity & increase tax revenues by quickly identifying undocumented improvements. • Objective of Sketch Check is to VERIFY whether data is accurate • Objective of ChangeFindr is to DETECT CHANGE within a jurisdictionYellow:Sketch Check Layer • ChangeFindr can be positioned asRed: ChangeFindr BOC an aid for future sketch management Note: Sketch Check shapefiles cannot be used for ChangeFindr projects & vice versa
  • 38. Advantages• Imagery (ortho/oblique/street-side): enable desktop review• Change Detection: Identify parcels with building changes• Sketch Check: Identify data accuracy issues.• Prioritized Review: Scoring Table makes it easy to prioritize which parcels to review first• CAMA/Workflow integration• Single Source: Pictometry offers all components of IAAO’s standard for remote desktop appraisal