Parcel Change Detection

All parcel
Pushpin recognizes all parcel changes, not just changes to the main structure
Pushpin classifies changes into 10 categories, facilitating desktop review prioritization
< 4 week
Pushpin is 10X faster than the competition, completing countywide projects in weeks
15¢ per
Pushpin is 5X cheaper than the competition, charging just 15¢ per parcel for projects with 100K+ parcels


  • Pushpin provides a next-generation property change detection service leveraging a patent-pending, semi-automated workflow that consistently achieves human-level accuracy or better.
  • Pushpin flags changed parcels, indicates one or more change type, and divides parcels into geographic sectors. Pushpin delivers all of this at 5X lower cost than the competition.
  • Pushpin’s accelerated workflow enables us to turnaround countywide projects with hundreds of thousands of parcels in less than four weeks.
  • For details, watch the demonstration video, review the datasheet, or browse the presentation.

How it works

  • Pushpin developed the world’s largest parcel change detection training set. Each sample in the training set contains a parcel boundary with old and new high-resolution, leaf-off imagery. A map analyst trained in property assessment assigned a changed/unchanged label to each sample. For changed parcels, the analyst also assigned one or more change types (addition, construction, deck, demolished, flatwork, garage, new, other, pool, or shed).
  • Pushpin then used these samples to train, validate, and test a state-of-the-art convolutional neural network (CNN) to recognize changed parcels. Specifically, we use a custom network derived from the 50-layer residual network (ResNet50), which won the ImageNet Large Scale Visual Recognition Competition (ILSVRC) in 2015. Pushpin uses this custom neural network to automatically compare old and new images and classify each parcel as changed or unchanged.
  • Pushpin breaks projects into batches of 500 parcels. Pushpin first uses the neural network to classify all batches. Map analysts then review 20% of the parcels in each batch. If the label agreement is 95% or greater, the batch is complete. Otherwise, a map analyst manually classifies the batch and another analyst reviews the result. Using this approach, we consistently achieve a project accuracy of 95% or better.
  • Competing approaches are completely manual and rely on building outlines. Unfortunately, relying on building outlines misses many changes that affect assessed value including non-building changes (e.g. a new deck, driveway, patio, pool, sauna, or spa) and changes that minimally impact the building outline (e.g. a teardown that utilizes the previous foundation).


For projects with at least 100,000 parcels, we charge 15¢ per parcel. For smaller projects, we 25¢ per parcel. Sign up for our trial and we will analyze 1,000 parcels for free.

Case Studies

Hennepin County, Minnesota

Tax Impact

Pushpin analyzed changes in 11,637 parcels in Hennepin county, Minnesota. The largest city in Hennepin county is Minneapolis. Pushpin used 1-foot, leaf-off imagery captured in the spring of 2009 and 2015 by Surdex. Pushpin found that 13% of the parcels had changes affecting assessed value. Extrapolating to the county’s 434,208 parcels, this represents a potential annual property tax revenue increase of $28.9M. The following table summarizes the findings. For details, read the full report.

Change Type Frequency Tax Impact
Addition 3.1% $5.1M
Construction 0.4% $0.1M
Deck 0.8% $0.3M
Demolished 0.1% $0.0M
Flatwork 8.1% $1.4M
Garage 0.4% $0.5M
New 2.7% $21.2M
Other 0.4% $0.1M
Pool 0.3% $0.1M
Shed 0.3% $0.1M

Hillsborough County, Florida

Tax Impact

Pushpin analyzed changes in 112,959 parcels in Hillsborough county, Florida. The largest city in Hillsborough county is Tampa. Pushpin used 6-inch, leaf-off imagery captured in the spring of 2014 and 2018 by Pictometry. Pushpin found that 10% of the parcels had changes affecting assessed value. Extrapolating to the county’s 530,632 parcels, this represents a potential annual property tax revenue increase of $29.2M. The following table summarizes the findings. For details, read the full report.

Change Type Frequency Tax Impact
Addition 1.5% $3.1M
Construction 0.2% $0.1M
Deck 0.1% $0.1M
Demolished 1.6% $0.0M
Flatwork 2.6% $0.5M
Garage 0.2% $0.3M
New 2.6% $24.7M
Other 0.0% $0.1M
Pool 0.5% $0.3M
Shed 0.3% $0.2M



Raymond Gottner

Director of Residential Valuations, Cook County Assessor's Office

Pushpin's results have been a game changer for us. Keeping our staff safe while efficiently managing their time in the field is a complex balancing act. Pushpin equips us with better information before we even leave our desks. We see a lot of value in their platform in our future work.

James Cowan

County Assessor, Payne County, Oklahoma

Our experience with Pushpin has been exceptional. From our test run a few months ago to our recently completed full county project, Randy and his team at Pushpin have been a joy to work with. The work was completed ahead of schedule and fit our budget nicely. We will definitely be working with Pushpin on future projects.

Paul Brodeur

Mayor, City of Melrose, Massachusetts

Melrose Chief Assessor Chris Wilcock has done a remarkable job of pivoting quickly during this pandemic to keep assessing operations running and keep state mandated property verifications moving forward. The ability to use artificial intelligence software like Pushpin to track property changes from last year without driving all over the city is the type of solutions that we need right now.

Steve Bauman

County Appraiser, Shawnee County, Kansas

The appraiser’s office selected Pushpin for our parcel change detection project because Pushpin’s accuracy is excellent and their service is much faster and cheaper than the competition. Pushpin helped us identify numerous property changes such as additions and new construction that were not in our permit database. Their specific identification of the changes enabled our staff to focus on the higher priority changes such as new construction and garages first.

KC McDade

Director of Operations, Williamson Central Appraisal District, Texas

In just two weeks, Pushpin extracted pool outlines and provided accurate measurements that we integrated into our CAMA system. Pushpin's turnaround time was fast, and their ability to infer pool shapes and provide accurate outlines of pools, even if obstructed from view by buildings, vegetation, etc., was very impressive. We are looking forward to working with Pushpin on future projects.

Dr. Rob Newman

Chief Executive Officer, Nearmap

By acquiring Pushpin's 3D geometry extraction technology and pairing it with our rich data, we bring the best of both worlds together at unprecedented scale. Over the past couple of years, we've evolved our offering from 2D imagery to a multi-product portfolio, and this acquisition is an important milestone in our approach to continue adding new content types for our customers. This addition aides our company mission by providing 3D geometry data at unmatched speed, thereby changing the way our customers perform their work.

Mikhail Palatnik

Executive, Product Management, CoreLogic

Pushpin is one of the only companies applying cutting-edge deep learning techniques to aerial imagery to automatically extract features and identify changes. It has been a pleasure working with Pushpin's innovative team. Going forward, we expect machine learning to be critical to creating and maintaining accurate property records, which our customers rely on.

Bob Henriquez

Property Appraiser, Hillsborough County, Florida

Pushpin enabled us to analyze our zone 3 properties in a fraction of the time and cost that was previously possible. We performed a careful review of the results and were so pleased that we asked Pushpin to analyze our zone 4 properties in the next fiscal year. We enjoy working with innovative partners like Pushpin that enable us to lower costs and increase efficiency.

Michael Wacker

Assessor, Pope County, Minnesota

Pushpin enabled us to increase property tax equity and revenue by identifying parcels with changes, but no relevant permits. Without Pushpin, it may have been years before we discovered these changes. Pushpin is leveraging machine learning to accelerate a process that historically has been slow and expensive. Their approach provided an excellent return on investment for our office.

Ken Wilkinson

Property Appraiser, Lee County, Florida

We fly new aerial photographs of Lee County every year to help with our parcel inspection and valuation process. Pushpin allows us to leverage that investment by identifying changes in parcels without costly on-site inspections. Having a full accounting of new construction, additions and demolitions is important in developing a fair and equitable tax roll for everyone. Pushpin is a great new tool we plan on utilizing to increase the accuracy of our data collection process.

Dave Dawley

Assessor, Carson City, Nevada

Pushpin delivered high-quality results in days versus months and did so at one-fifth the cost of the competition. Pushpin is applying to property assessment the same kind of artificial intelligence algorithms that Google used to beat world champion Go players. The result is a dramatic improvement in accuracy, turnaround, and cost—and a phenomenal return on investment.

Eric Bails

Chief Technology Officer, Maricopa County Assessor, Arizona

Pushpin is applying to real property assessment the same kind of artificial intelligence algorithms that Google uses in its autonomous cars. Our testbed was a set of four areas of the county, each of which presents a different challenge for change detection via aerial photography. After we examined these small pilot areas with this constantly learning technology, we believe our office has a new opportunity to improve the accuracy, turnaround time, and cost for detecting a variety of changes.


Founded in 2015 and based in Minneapolis, Pushpin believes that people and computers intelligently combined can solve difficult mapping challenges better, faster, and cheaper than the alternatives. Pushpin works with tech-forward clients and partners to dramatically increase automation, accelerate workflows, and decrease costs. Pushpin applies patent-pending deep learning algorithms to aerial and satellite imagery to identify parcel changes, extract building footprints, estimate impervious areas, and more. Pushpin has worked with 62 cities and counties in 21 states as well as partners such as CoreLogic, CycloMedia, and Nearmap.


The following are Pushpin’s principals. Pushpin also has a team of 48 GIS analysts who assist with training set creation and quality assurance.

Randy Milbert

Founder and President

Pushpin's founder and president is Randy Milbert. Randy graduated from the Massachusetts Institute of Technology (MIT) in 2000 and founded Primordial in 2002. At Primordial, Randy led the development of the company's Ground Guidance® off-road navigation software and Ooze® crowdsourcing geographic information system (GIS) platform. He secured more than $15 million in contracts from the United States Army, United States Air Force, Missile Defense Agency, Rockwell Collins, General Dynamics, Lockheed Martin, Polaris Industries, and others. He received six issued and three pending patents. In 2012, the Army acquired a government-wide license for Ground Guidance. In 2013, Polaris Industries (NYSE:PII) acquired Primordial. In 2015, Randy left Polaris Industries to found Pushpin.

Andreas Robinson

Chief Technology Officer

Pushpin's chief technology officer is Andreas Robinson. Prior to joining Pushpin, Andreas was an early hire and senior engineer at Primordial where he led multimillion dollar Army, Air Force, and DARPA projects including developing an aerial vehicle-based geospatial tracking system, an augmented reality platform for dismounted soldiers, a learning-based navigation system, and a machine learning application for extracting features from satellite imagery. Prior to Primordial, he developed neural networks for flush-air sensor systems at Goodrich Aerospace (now United Technologies). He has a masters degree in computer science from the University of Minnesota from 2004 and a physics and math degree from Reed College from 1999.

Grady Hannah

Vice President Business Development

Pushpin's vice president of business development is Grady Hannah. Grady is an 18-year technology sales and business development veteran, spending 15 years in senior roles in tech-forward Silicon Valley companies. These markets include manufacturing industries, real-time entertainment software, Linux and open source software, and alternative energy. Grady's experience in the assessor market comes from a sales role for ground-based image capture company Facet Technologies. Grady's role at Pushpin is to sell and market Pushpin's image-based change detection and feature extraction capabilities to all relevant markets including county, city and state governments, emergency services, GIS, ISV partners, and discrete map creation applications.

Scott Sherwood


Scott Sherwood retired from EagleView (formerly Pictometry) in 2017. He joined Pictometry as a startup in 2000 and served in various sales and marketing positions over 17 years including vice president of sales (northern region), vice president of corporate marketing initiatives, and vice president of sales enablement leading up to the merger with EagleView in 2013. While at EagleView, he was responsible for product development strategy for the public safety market. Prior to Pictometry he was with the Center for Governmental Research Inc. in Rochester, NY for 26 years where he served as the director of technical services responsible for project management in environmental planning, land use planning, and public safety applications of GIS and GPS.


Pushpin is headquartered in Minneapolis, Minnesota.

Feel free to contact us anytime at 651-216-6941 or

Try for Free

Pushpin will analyze 1,000 parcels in your county for free. Please use the following form to provide your contact information. We will follow up to obtain the relevant parcel boundaries and imagery. Once we have that, we will deliver final results within five business days.