How well does a virtual street tree survey work?

Dr. Adam Berland Ball State University

http://vision.caltech.edu/registree/

L.A. wants Caltech and Google to count the city's trees

-LA Times July 27, 2016

Can we generate quality data using a virtual survey in GSV?

© 2016 Google

Cincinnati suburbsMt. HealthyReadingWyoming

Field data (2013)

All trees on >10% sample of local streets

Virtual survey analyst: Bachelor’s in field botany

© 2016 Google

RESULTS10 miles of street length

Field survey 597 treesVirtual survey 606 trees93% ‘matched’ Time mismatch for field/virtual

Genus agreement: 90%Species agreement: 66%

Large, common, distinctive

© 2016 Google

Berland & Lange (in review)

1-to-1 line

Regressionline

Slope = 0.79R2 = 0.80

Imagery © 2016 Google

Energ

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100,000200,000300,000

Virtual Field

Annu

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i-Tree Streets: Virtual survey ~10% lower than field survey

Performance recapTree count / location

Tree ID

Size (DBH)

© 2016 Google

© 2016 Google

RecommendationsDoes not replace field surveysFree & easy approachCoarse variablesUpdate existing inventories

Questions / comments / ideas

Adam Berlandamberland@bsu.edu