#1 Improv, #2 Morse, #3 Kompressed, #4 Ship Finder, #5 High Altitude Balloon Path, article When Satellites Go Quiet, People Notice, on X Watch Agadez grow (be built), then handed back, to now. Northern Niger. Keep on eye on it!

#1 Improv#2 Morse#3 Kompressed#4 Ship Finder#5 High Altitude Balloon PathArticle When Satellites Go Quiet, People NoticeOn X Watch Agadez grow (be built), then handed back, to now. N...
Marshall Frith

ChangeLens

ChangeLens

Before and after for anywhere on Earth, from free Copernicus Sentinel images. No account, ads, or analytics.

Marshall Tyler Frith

ChangeLens is an iPhone and iPad app for comparing two dates of the same place. Search for a place, pick a Before and an After date, and drag the divider across two free Copernicus Sentinel images to see what changed: a new neighborhood, a flooded river, a harvested field, a retreating glacier.

This page is the App Store Support landing for ChangeLens.

What it does

  • Search by place name, address, or coordinates, then drag the square on the map to frame a 1, 3, or 10 km area.
  • Pick two dates. ChangeLens finds the nearest scene with little cloud over your area and tells you when it had to move the date.
  • Switch layers: True color, SWIR (vegetation, water, bare or burned ground), Radar (Sentinel-1, works through cloud), and Blend.
  • Drag or tap the divider, and pinch to zoom both images together.
  • Share or save the comparison as an image, with the dates, a scale bar, a north arrow, and the Copernicus credit line.

Requirements

  • iPhone or iPad with iOS 17 or later
  • Internet connection to find and load the images
  • No account. Photos permission (add only) is asked for only if you save an image to your library.

Privacy

Privacy Policy: Data Not Collected. No account, no ads, no analytics, no tracking, no ChangeLens servers.

Support

Questions, bug reports, or App Store review contact go through the contact form with ChangeLens in the subject. Messages reach Marshall Frith directly.

Imagery: contains modified Copernicus Sentinel data. Radar images are processed by Microsoft Planetary Computer. Not affiliated with the European Commission, ESA, or Microsoft.

App Store

iPhone and iPad · Bundle com.marshallfrith.changelens