835 search results for "maps"

R for spatial analysis tutorial + video

January 30, 2014
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On 24th January 2014 I ran a one day practical course on an "Introduction to Spatial Data Visualisation in R" at the University of Leeds, with the help of demonstrators Rachel Oldroyd and Alistair Leak, who came up from London for the event. The course is designed for people completely new to R, who are especially interested in its spatial...

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Importing bathymetry and coastline data in R

January 25, 2014
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Importing bathymetry and coastline data in R

After noticing some frustrating inaccuracies with the high-resolution world coastlines and national boundaries database found in worldHires from the package mapdata (based on CIA World Data Bank II data), I decided to look into other options. Although listed as "depreciated", the data found in NOAAs online "Coastline Extractor" is a big step forward. There...

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Visualizing Autoregressive Time Series

January 21, 2014
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Visualizing Autoregressive Time Series

In the MAT8181 graduate course on Time Series, we started discussing autoregressive models. Just to illustrate, here is some code to plot  – causal – process, > graphar1=function(phi){ + nf <- layout(matrix(c(1,1,1,1,2,3,4,5), 2, 4, byrow=TRUE), respect=TRUE) + e=rnorm(n) + X=rep(0,n) + for(t in 2:n) X=phi*X+e + plot(X,type="l",ylab="") + abline(h=mean(X),lwd=2,col="red") + abline(h=mean(X)+2*sd(X),lty=2,col="red") + abline(h=mean(X)-2*sd(X),lty=2,col="red") + u=seq(-1,1,by=.001) + plot(0:1,0:1,col="white",xlab="",ylab="",axes=FALSE,ylim=c(-2,2),xlim=c(-2.5,2.5)) + polygon(c(u,rev(u)),c(sqrt(1-u^2),rev(-sqrt(1-u^2))),col="light yellow")...

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Second NYC R classes(announcement and teaching experience)

January 20, 2014
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Second NYC R classes(announcement and teaching experience)

(The photo was from our first offering of R classes) We are going to offer our Data Science by R (beginner level) course again in February. The goal of this class is to get students to a point where they are self-sufficient in R, are proficient at analyzing data and can take these skills back to their full-time jobs....

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Statistical Interests in Large Cities

January 10, 2014
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Statistical Interests in Large Cities

I always thought that there were some kind of schools in statistics, areas (not to say universities or laboratories) where people had common interest in term of statistical methodology. Like people with strong interest in extreme values, or in Lévy Processes. I wanted to check this point so I did extract information about articles puslished in about 35 journals...

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Spatial clipping and aggregation in R

January 10, 2014
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Spatial clipping and aggregation in R

A common task in GIS is comparing the spatial extent of one layer with another. Say you have a load of points, some of which overlay a polygon layer. You are only interested in the points that intersect with the points. What do you do? Also, how can you aggregated-up the values contained in the points to correspond with the...

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Spatial clipping and aggregation in R

January 10, 2014
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Spatial clipping and aggregation in R

A common task in GIS is comparing the spatial extent of one layer with another. Say you have a load of points, some of which overlay a polygon layer. You are only interested in the points that intersect with the points. What do you do? Also, how can you aggregated-up the values contained in the points to correspond with the...

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dcemriS4 0.51

December 30, 2013
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dcemriS4 0.51

The R package dcemriS4 provides routines for the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), along with quantification of diffusion-weighted MRI (DWI) and quantitative T2 maps from CPMG sequences.  The ...

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K-means Clustering 86 Single Malt Scotch Whiskies

December 30, 2013
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K-means Clustering 86 Single Malt Scotch Whiskies

by Luba Gloukhov The first time I had an Islay single malt, my mind was blown. In my first foray into the world of whiskies, I took the plunge into the smokiest, peatiest beast of them all — Laphroig. That same night, dreams of owning a smoker were replaced by the desire to roam the landscape of smoky single...

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Statistics unplugged

December 27, 2013
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Statistics unplugged

How much does statistical software help and how much it interferes when teaching statistical concepts? Software used in the practice of statistics (say R, SAS, Stata, etc) brings to the party a mental model that it’s often alien to students, while being highly optimized for practitioners. It is possible to introduce a minimum of distraction

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