Comparing MassGIS imagery, 2015–2021

Compare the same location near Egremont, Massachusetts, using MassGIS satellite imagery acquired in spring 2015 and aerial imagery acquired in spring 2021. The view uses the official tiled services and a common top-down map extent.

Load the comparison, then move the slider to reveal either date. Pan and zoom to examine buildings, roads, vegetation, and land use. Differences in acquisition date, season, sensor, resolution, and processing affect how features appear. Record these conditions when using imagery to support a baseline or change assessment.

The 2015 layer combines WorldView satellite acquisitions from 16 March to 7 May 2015. The 2021 layer is spring aerial orthoimagery published from 15 cm RGB source imagery. These are historical observations; use the MassGIS image-data catalogue to identify other dates and obtain the original metadata.

Acknowledgements

Thanks to Dr. Sudhira H.S. for introducing me to imagery comparison. Imagery is provided by DigitalGlobe and MassGIS for 2015, and MassGIS for 2021.