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Detect and correct property data errors quickly using Sketch Verification

If you’re an assessor trying to figure out how to correct and resolve physical property data errors efficiently, then Sketch Verification Professional Services is what you need. Sketch Verification Professional Services can help you save countless hours in identifying sketch measurement discrepancies and property changes that have occurred over time (e.g., additions). You can use this service to help meet your property inspection requirements, data correction projects, as well as advance your Desktop Review initiatives. With Sketch Verification Professional Services, your organization can accelerate the path towards clean data and free up your time, so you can focus on other valuation activities. 

In assessment, planning ahead is fundamental yet challenging, especially when you consider cyclical processes, compliance requirements, staff shortages and the extensive amount of ongoing work required to maintain accurate property data. Even when staff shortages don’t exist, it can be difficult to align resources in the most efficient way to ensure data accuracy objectives are met. To add to this, imagine having thousands of land parcel sketches to physically review and verify. Phew!

As a property assessor, you understand the importance of accurate and reliable data in the property assessment process. However, errors in the process of collecting and verifying property data do come up. What do you do about them? 

This is where Sketch Verification Professional Services come in.

Our experienced consultants help verify if your property sketches accurately represent the size, shape and features of the property being assessed. This involves checking the dimensions of the property, verifying the location of buildings and other features on the property, and ensuring that the sketch matches the actual property boundaries. Sketch Verification Professional Services support IAAO standards for Mass Appraisal - 3.3.5 Alternative to Periodic On-site Inspections and can provide your Assessment department with the clarity you need to determine how and where to best focus your resources to correct and resolve physical property data errors. With Sketch Verification Professional Services, our consultants can help you identify geographic areas that require more of your attention and determine how you can efficiently assign workflows to your team.  

Sketch Verification Professional Services help you detect data errors through analysis of sketch files, which are then converted to an Esri Features class and are georeferenced to ensure accurate property orientation. The georeferenced sketches are then compared through visual inspection to the most recent ortho-imagery to determine if the sketches are a match, major mismatch (over 100 sq. ft. variance) or minor mismatch (under 100 sq. ft. variance). The results are delivered in three formats—a geodatabase, spreadsheet and project summary (pdf) report. These deliverables identify sketch measurement errors, property changes over time (e.g., new construction and/or demolition that have not been detected and accounted for) and detailed summaries that allow for visualization of data errors.

Thematic map showing results

Thematic map showing results

Project summary results

One of the deliverables you’ll receive is a detailed project summary (pdf) report.

Images identifying if the sketches are a match, major mismatch or minor mismatch.

Reports include images identifying if the sketches are a match, major mismatch or minor mismatch. 

Conversion and creation from existing sketch to Esi feature class based on Unique ID (Roll Number)

Conversion and creation from existing sketch to Esri feature class based on Unique ID (Roll Number)  

Why use Esri Canada’s Sketch Verification Professional Services?

Improve your data accuracy. Reduce errors in your property valuations and assessments by verifying that property sketches accurately represent real-world features of the property being assessed. This can help ensure that property taxes are more fairly and accurately levied.

Streamline your data collection. Collect and verify property data without having to go on site. Imagine the time and resources you’ll save by automating the identification and correction of errors in hand-drawn or digitized sketches.

Make better decisions. Have accurate, reliable and complete property assessment data to make more informed, defensible decisions.

If you want to ensure your property valuations and assessments are fair, transparent and based on the most accurate data available, explore Sketch Verification Professional Services.

To book a free consultation, email us at

You can also explore Esri Canada's entire suite of assessment products and services at   


About the Author

Danny Gioia is the Account Manager for Assessment Analyst. While pursuing a Bachelor of Commerce at the University of Guelph with a major in Real Estate and Housing, Danny developed a strong interest in real-estate valuation. He took the next steps to qualify for a career in Assessment through enrolling in the PGCV and Certificate Program in Real Property Assessment at the University of British Columbia. This opened the opportunity for him to join the Assessment industry at the City of Calgary to pursue his passion for real estate valuation. After working as an assessor for 2+ years, he continued his career in technology sales. In his free time Danny likes to travel and cook, as well as try new restaurants – especially when travelling!

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