Discussion: Global Forest Watch

As if one thread on climate change wasn't enough: An interesting website:

http://www.globalforestwatch.org/

A partnership between World Resources Institute and about 40 other organizations has created Global Forest Watch (GFW): A free online forest monitoring system that can detect changes in tree cover in near-real-time, using satellites, Google Maps, Google Earth and a variety of other resources

Doesn't Google Maps only update their on-line satellite imagery about every five years? Actually I don't really know since the images I'm using for mapping seem to be years out of date.

Google's imagery is at most 2 years old around here (in Google-land). It often does not have the best accuracy, but usually has the best resolution, 6 to 10 cm in most cases.

Not really real-time (or even near-real-time) then.

I think they use Google Maps for the base map, the forest cover comes from satellite data.

Google is providing the computing power rather than satellite imagery for the project - http://googleresearch.blogspot.com.au/2013/11/the-...

Thanks for the link O-ing. The remote sensing data does a decent job of mapping the fire scar at one of my wildfire research sites in Alberta.

https://twitter.com/nkettridge/status/437884214738...

I think Google Maps updates their imagery (satellite and aircraft) whenever new imagery becomes available. The only stuff they collect themselves is StreetView. I'm not certain, but I think satellite images are actually the lowest quality last resort, and the good photos are taken from aircraft, which are not constantly in orbit.

StreetView is even older than the satellite images on their website, at least in Perth they are. I think they've only ever been through here once and people complained (as people tend to do).

Right. For StreetView, they're probably concentrating more on adding to the area rather than updating places they already have. Google has a limited number of StreetView vehicles and a lot of area yet to cover. For aerial photos, different places get new surveys for various reasons. I would expect that the newest photos would be of remote areas, where there are no aircraft photos available, and the best they can get are satellite photos, which are the lowest quality, but updated fairly often.

If I build a forest in my front yard, will they get a plane to fly over for the above project?

I find their data product annoying, because it causes people to confuse disturbance (forest fires or harvesting, for example) after which the area in question remains a forest (albeit with very small, young trees that can't be detected from space) with forest cover loss. Actual forest cover loss can only happen if we proceed to build houses or golf courses or fields for growing crops.

If I zoom into the area north of where I live, it shows all kinds of forest gain and loss, whereas I know the entire area has never been anything but forest for centuries.

Yes loss is the wrong term and makes it appear worse than it is. Those fires are essential.

Google doesn't hire the planes, or influence what they photograph. It's all about other parties (such as regional governments) flying the surveys and making the results publicly available.