As the world turns

As a geographer and long-time GIS user, I have used removed sensing imagery for decades.  I just love looking at remotely sensed images of the world — especially when you can compare how things have changed with time. Various satellites have been collecting this data for decades — and while much of it is public available it can be a pain to assemble tile after tile of data and massage it until you have something presentable.

Fortunately, at a Bay Area Open Space Council meeting this morning, a Google Earth product manager showed me that there is an easier way. It’s called Google Earth Engine. They’ve collected terabytes of Landsat imagery and spent two million hours developing a seamless image map for the Earth that can take you back to 1984 (that’s when Frankie was encouraging us to “Relax” and Cyndi Lauper was having “fun’.)

I took a quick look at some places I know well. First, it’s an era that spans the timber wars centered around the Headwaters Forest Reserve. Scroll time forward and you can watch the mosaic of cuts getting closer and closer to what is now a remarkable upland ancient redwood forest protected by BLM.

HRSP Earth Engine
Landuse changes around Headwaters Reserve (clink for live slideshow)

I then got curious if you could similarly see changes in and around Santa Monica and southern California over the same period. Here the changes on the surface are subtler. Look carefully you can see development in the mountains as hillsides give way to large areas of bare soil and then homes. And perhaps I am imagining it, but it looks to me that some of the parks along the river channels are starting to green up!

Santa Monica City and Bay in Earth Engine (click for slideshow)
Santa Monica City and Bay in Earth Engine (click for slideshow)

It’s pretty exciting to have this level of data at our fingertips now. And it just keeps getting better and more powerful with multi-spectral data coming along that will enable us to move beyond looking at pictures of change, to conducting sophisticated analysis — all right in our browser.

Why don’t you jump on the Earth Explorer website and see how places you care about have changed — either for the worse, or just perhaps for the better? Let me know what you discover!

 

[p.s. couldn’t figure out how to embed the Google maps directly in this post…..sorry!]

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