Applications of historical aerial imagery: georectification, classification of land-use/land cover for Baltimore City in 1927 relative to present-day urban woodlands

Keywords: historical land use land cover, urban forest patches
Session Type: Virtual Paper Abstract
Day: Monday
Session Start / End Time: 2/28/2022 05:20 PM (Eastern Time (US & Canada)) - 2/28/2022 06:40 PM (Eastern Time (US & Canada))
Room: Virtual 50

Abstract

The distribution of landscapes that seem like “nature” or “wilderness” are actually the result of complex social histories. This project seeks to understand the relationships among people, communities, and forests in Baltimore, MD over the past 100 years. Analyzing the landscape is typically done through the automation of land use and land cover (LULC) classifications with GIS software using spatially explicit color aerial imagery. In contrast, classifications of black and white historical aerial photographs present several challenges that require a combination of techniques and novel approaches. We analyzed 93 aerial images covering 544 km2 within and surrounding Baltimore taken from a bi-plane between 1926-27. High-resolution images were georeferenced to modern satellite imagery of the area and then digitized into a LULC classification. 2015 urban tree canopy and forest patch layers were overlaid with a simplified version of the 1927 LULC classification in order to determine the historical land cover of present-day tree canopy and forest cover within Baltimore City. About 60% of present-day forest cover was forested in 1927, another 30% was classified as non-forest vegetation in 1927, and the remaining 10% of present-day forest was made up of residential, industrial, or other urban development in 1927. Within the present-day forest cover of Baltimore City, larger forested natural areas are much more likely to have been forested in 1927, rather than classified as non-forest vegetation or developed. These insights may help inform future environmental planning, conservation, management, and stewardship goals for Baltimore forest patches, and other cities throughout the region.