Mapping Hacks

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Chapter 6, Mapping on Your Desktop

#77 Become a GRASS Ninja

HACK

Finally, we can use r.sum to estimate how many people live in the poten-

tially submerged areas:

GRASS 5.7.0:~/gis/europe > r.sum displaced

Reading displaced... 100%

SUM = 41109241.000000

Our answer is that about 41 million people will be displaced from their

homes in Western and Central Europe, should the current sea levels rise by

10 meters. That’s more than one in every 15 people! If we perform the same

analysis for the East Coast of the United States, we find that as many as 25

million people there may be displaced, and, mind you, all this is based on

population data that is already 10 years old. We haven’t performed this

analysis for, say, Bangladesh or Southeast Asia, but you can do the math

yourself.

Conclusion

As you can see, GIS is more than just about making maps; it offers us the

chance to explore and explicate the state of our world not only in the past

and present, but our future as well. The conclusion that we’d like you to

draw is not that chaos and disaster are the eventual lot of humanity,

although that may turn out to be the case. Instead, we hope that this exer-

cise presents a cautionary tale about one possible future and that, through

education and communication, our fate as one species among many on this

precious planet may yet turn out bright.

HACK

#77

Become a GRASS Ninja Hack #77

Or, Zen and the Art of open source ...