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Showing posts with label USGS. Show all posts
Showing posts with label USGS. Show all posts

Wednesday, May 23, 2012


Mapping Global Earthquake using XML and Maptools

Everyday the US Geological Survey (USGS) publish earthquake data (http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_all.html) all over the globe. Using XML and maptool packages of R I downloaded and map USGS earthquake data using the following codes :

library(XML)
usgseq<-"http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_all.html"

weq1 = readHTMLTable(usgseq, header=T, which=1,stringsAsFactors=F)
weq2 = readHTMLTable(usgseq, header=T, which=2,stringsAsFactors=F)
weq3= readHTMLTable(usgseq, header=T, which=3,stringsAsFactors=F)
weq4 = readHTMLTable(usgseq, header=T, which=4,stringsAsFactors=F)
weq5 = readHTMLTable(usgseq, header=T, which=5,stringsAsFactors=F)
weq6 = readHTMLTable(usgseq, header=T, which=6,stringsAsFactors=F)
weq7 = readHTMLTable(usgseq, header=T, which=7,stringsAsFactors=F)
weq8 = readHTMLTable(usgseq, header=T, which=8,stringsAsFactors=F)

eq<-rbind(weq1,weq2,weq3,weq4,weq5,weq6,weq7,weq8)


weq<-eq[,c(2,4,5)]
x<-as.numeric(weq[,3])
y<-as.numeric(weq[,2])
z<-as.numeric(weq[,1])

library(maptools)
data(wrld_simpl)
plot(wrld_simpl, col="green4", border="white", axes=T)

plot(wrld_simpl, col="green4", border="white")
points(y~x, cex=(z^2)/12, col=ifelse(z>5,"red","blue"), pch=19)
text(0,101,"Global Earthquake Maps (May 15-23,2012)", cex=1.8)
text(-180,-95,"Data Source: USGS\nCreated by: ARSalvacion", adj=0, cex=0.5)