Daily Archives: October 10, 2011

Fun with GIS #92: Changing Times

It’s Earth Science Week, and the theme is “Our Ever Changing Earth.” Change happens at many scales, and Esri’s Landsat application, “Change Matters,” helps users explore those that are football field size and up, since 1975. See this blog entry introducing the “Change Matters” app; it’s important to learn how to work with the app, and the introductory tour is a great start.

If you’ve gone through the earlier blog and tour, let’s try two different kinds of examples. For Example One, click this shortcut. Keeping the location and scale constant, just change the year, and try to spot changes from one period to the next. Next, turn on the “Overlay Change” layer, and check the three time periods 1975-1990, 1990-2000, and 2000-2005. There seems to be a huge increase of vegetation in the last stretch. Can you tell why? (Hint: Turn off the “Overlay Change” and, in the “Infrared” box at bottom, click “Click image to see Metadata”, and compare the 2000 and 2005 images.)


Click to enlarge

Lots of good things to explore in Example One. What sorts of processes might be leading to the changes that are visible?

For Example Two, click this shortcut. Again, keep the scale and location steady, and jump back in time from 2000 to 1990 and 1975. Go back to 2000 and turn on the “Overlay Change” layer, and check the three time periods again. The color changes are totally different pattern compared with Example One. What kinds of processes might be leading to the concentrated changes here?


Click to enlarge

The “Change Matters” application allows students and educators to see change on the macro scale, football field and above. Because of the changes that are visible at this scale, other changes are occurring in the regions pictured. What kinds of changes might those be, and at what scales would they be visible?

Our ever-changing Earth provides a number of fascinating studies, and the “Change Matters” application helps demonstrate the power of geospatial technology for cataloguing and analyzing change. These capacities relate to a vast number of STEM careers crucial to be filled, as we struggle to preserve our ways of life and our biodiversity.

- Charlie Fitzpatrick, Esri Education Manager

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