App shows changes to NYC’s landscape over the past 90 years

Aerial photos of the city, some dating to 1924, will be made public with a new app, launching Wednesday.

The NYC Then & Now app will allow users to compare photos from the past nine decades by selecting multiple years and using a slider to switch back and forth.

The city’s Department of Information Technology and Telecommunications has used these images in the past for projects such as updating hurricane flood zones and identifying beach quality.

DoITT Commissioner Anne Roest said the department hopes New Yorkers will use the historical data and maps to make their own apps, reports and slideshows.

“We hope to see many more enriching NYC-focused tech products built using this valuable source material,” she said.

The site includes thousands of aerial photos taken in 1924, 1951, 1996, 2001 and biennially since 2002. The most recent photos, which were shot from a plane at 8,200 feet, were taken in spring 2016.