1. Now that the imagery is available what elsecan you do with it??? Answer: Sketch Validation Sketch vectors exported from CAMA system Geo-referenced, rotated, and anchored to the structure on the aerial ortho image. GIS sketch layer created Invalid findings greater than 100 square feet identified Using this process ALL sketches of improvements are validated and can be considered as digitally re-measured Appraisers work with the validation software to correct any invalid sketches from a queue. Increases accuracy of sketches and adds missing value to the appraisal role. Sketch Validation

2. Upon completion of the project, the vectors are delivered in a GIS shapefile format.

3. Why Do Sketch Validation? Manual re-measure estimated cost*: WCAD Improved Properties (2009) = 135,000 (x) Re-measured per hour = 6 Hours to Re-measure = 22,351 = 10.75 years (x) Avg. Appraiser Salary = $60,000 Estimated Cost of Manual Re-Measure = $644,740 Gained taxable value needed to recover $644,740 = $28,655,120 * This estimate is only Appraiser Cost (No Entry)

4. Sketch Validation Software & Service Cost: WCAD Improved Properties (2009) = 135,000 (x) Sketch Validation Cost Per Parcel = $0.43 Estimated Sketch Validation Cost = $58,050 Gained taxable value needed to recover $58,050 = $2,580,000

5. Estimated Cost of Manual Re-Measure = $644,740 Estimated Sketch Validation Cost = $58,050

6. Sketch Validation Results: 11% invalid findings Total value added to role: $88,530,128 Estimated Total Taxes in Year 1: $2,213,253 Return on Investment for Year 1 Taxes Gained = $2,213,253 Total Cost to District = $135,620 ROI = 1632%

7. Accuracy of the appraisal role with fairness and equality of valuations Added value to role that increases tax base by adding missing improvements Cost effective when compared to manual re-measure Huge Return on Investment of monies contributed to your budget by the taxing units Increased credibility

8. Sketch Validation: Uses sketch vectors currently in your CAMA system Overlays sketches on most recent aerial photography Enables correction of invalid sketches efficiently Resulting in accurate sketches Change Detection: Compares the most recent aerial photograph of an improvement to a previous aerial photograph Changes are detected from these photographs Does NOT correct existing sketch errors Does correct missing improvements since last aerial photograph Sketch Validation Vs. Change Detection

10. Promotes data sharing

11. Purchase aerial ortho and oblique imagery

12. Increased visibility of improvements

13. Shared use and expense with taxing units

14. Geo-Reference (Rectify) your parcels

15. Enables immediate use of your parcel layer

16. Creates a more professional image to your taxing units and the public (increased credibility)Recommended Progression to Assist Taxing Units

17. Sketch Validation of Improvements Creates an accurate sketch of all improvements within CAMA system Change Detection of Improvements Continues accuracy of sketches by detecting changes from each version of your aerial photography Recommended Progression to Assist Taxing Units

18. Thank You! Alvin LankfordChief Appraiser alvinl@wcad.org Pamela OrrDirector of Operations pamo@wcad.org Williamson Central Appraisal District625 FM 1460Georgetown, Texas78626-8050(512) 930-3787