Getting it Done
Using GIS to Help Appraisal Staff Rapidly Update and Improve Property Data
Pete Coventry, Adam Hoppe Boulder County Assessor’s Office
GIS Department Boulder, Colorado
Overview • Boulder County • Assessor’s Office structure Data Mining • From the Assessor’s Database • Getting it into GIS
Focus on Residential Properties
GIS for Appraisal work • In the field • Capturing Attributes (valuation)
• Analysis & Modeling
Where we work
Geology.com
720 square miles One-third plains Two-thirds mountains 125,000 real properties 98,000 residential
Where we work
Diverse Landscape
Diverse Properties
Why is property Assessed • Basis for generating tax revenues for local services
Assessors Role • Identify and values property within the county in
accordance with state law • Equalize property values/ taxes distributed fairly
Re-valued every odd # year
How we work
Teams = Geographic Areas
Assessor’s GIS Department
Led by Cindy Braddock • 3 GIS Specialists • 3.5 GIS Techs Responsible for… A LOT!
Data Mining
Why and How • Requests for information
– Public, partners, other County departments
• Helps us improve quality of information • Understand what we’ve already got
– Right, Wrong, Inconsistent – Know what to fix
100’s of tables 1000’s of fields
Add tables Join on Key Field Set requirements/parameters
“Bubble” Maps
Permit Fieldwork • Status as of January 1st • Remodels, other high $ improvement adds
value • Generates tax revenue for our districts • New residential construction
– Vacant to residential changes assessment rate – Determined by existence of a foundation
Mountain Attributes Human Judgment: • View • Privacy • Access
Mountain Attributes GIS Terrain Analysis captured: • Topography • Aspect
Dick’s Views on Views
Field Data -> Excel Spreadsheets-> Mass Uploaded into Database
Examining Sales Ratios
Estimated Sales Price (ESP)/Time-Adjusted Sales Price • Any ratio between 0.95 and 1.05 is ‘acceptable’ • Sales ratios << 1.00 – UNDERVALUED ESP? • Sales ratios >> 1.00 – OVERVALUED ESP? • Cause: incorrect or missing property information?
Sales Ratio =
Planes, Trains & Automobiles…
Planes, Trains & Automobiles…
Actually… Power Lines, Towers, and Railroads
Planes, Trains & Automobiles…
…Automobiles (Traffic, really)
GIS Analysis
The Heartbreak of…
http://geology.com/articles/expansive-soil.shtml
2008
2008 - 2009
2008 - 2010
2008 - 2011
2008 - 2012
Thanks for attending! Any questions??
Adam Hoppe & Pete Coventry Boulder County Assessor’s Office
GIS Department Boulder, Colorado
Adam Hoppe – [email protected] Pete Coventry – [email protected]
Geographic Areas = 5 Models
Sales Ratio = 1.6
• Sold for $514,000 • TMADJ SP = $513,000 • ESP = $800,000 • Overvalued ESP • Time for review
Sales Ratio = 0.81
• Sold for $675,000 • TMADJ SP = $660,000 • ESP = $540,000 • Underestimated ESP • Appraiser will review property attributes to determine if incorrect or missing
Coming Soon…
Bye, bye ArcReader Hello ArcGISExplorer • More bells and whistles and flexibility for the
users (appraisers) • Much Faster • More customization on the front end which
helps deliver more useful maps • More programming… C#