Urban forest inventory using open access web mapping services and photogrammetric solution

Community-based data collection is a new trend that can empower and diversify our data collection methods and increase our understanding of the environment. As citizens are becoming more interested and involved in ecological matters utilizing their manpower and knowledge can be a new valuable resource for researchers and urban managers. Utilizing web mapping services to assist in collecting spatially related data can provide data that previously required dedicated personnel. National or regional programs for urban forest inventories that utilize trained crews, such as the UFORE program, were previously used exclusively. Much of the information collected by crews can be collected by interested community volunteers if combined with proper education and other resources such as high resolution aerial images and ground images. Our research tested the idea of utilizing a web application built around Google Mapstrade web-based service that allows users to actually select and input information about their backyard vegetation. We extended this idea by extracting metric information such as crown diameter, tree heights and diameters by solving close-range photogrammetric models for images captured using consumer-grade digital cameras and uploaded by participating citizens. The images were processed using one of the commercial photogrammetric software. Ground survey measurements made using survey equipment were collected and analyzed to test the accuracy of the photogrammetric model. We compared the results of the photogrammetric solutions with the higher-accuracy survey-quality measurements. The preliminarily results of this research demonstrated the potential for photogrammetry to provide valuable data for urban forest inventory programs.