Monthly Archives: July 2012

A Napa Valley wine tasting map, made with R and ggmap

July 9, 2012
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A Napa Valley wine tasting map, made with R and ggmap

R has had a maps package available since the very early days. It's great for simple geographic maps, but the political boundaries can be out of date. For more detailed maps, you can also download shape files and use the sp package to draw borders directly. But for accurate and attractive maps of countries, roads and satellite imagery, nothing...

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Map biodiversity records with rgbif, maps and ggplot2 packages in R

July 9, 2012
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Map biodiversity records with rgbif, maps and ggplot2 packages in R

Global Biodiversity Information Facility or GBIF is an international consortium working towards making Biodiversity information available through single portal to everyone.  GBIF with its partners are working towards mobilizing data, developing data and metadata standards, developing distributed database system and making the data accessible through APIs. At this point this largest single window data source covering wide spectrum of taxa and

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Example 9.37: (Mis)behavior of binomial confidence intervals

July 9, 2012
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Example 9.37: (Mis)behavior of binomial confidence intervals

While traditional statistics courses teach students to calculate intervals and test for binomial proportions using a normal or t approximation, this method does not always work well. Agresti and Coull ("Approximate is better than "exact' for interval estimation of binomial proportions". The American Statistician, 1998; 52:119-126) demonstrated this and reintroduced an...

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Trend and Spatial Pattern of Poverty in the Philippines

July 9, 2012
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Trend and Spatial Pattern of Poverty in the Philippines

In a teaching demo that I have conducted, I discussed on how R can be used to analyze trends and spatial pattern of poverty incidence in the Philippines. Playing on the data I got from the National Statistical Coordination Board below is what I got.&...

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leaf area measuring — R package “EBImage”

July 9, 2012
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leaf area measuring — R package “EBImage”

Besides microscopic images in our routine, common photos are frequently taken to measure quantitative plant features, such as leaf area, root length, branch numbers, etc. Scientific software is available for manual processing. For example, to measure the root length, one need to use the … Continue reading →

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Network Visualization of Key Driver Analysis

July 8, 2012
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Network Visualization of Key Driver Analysis

Whatever happened to those evaluations that your airline asked you to complete after taking a flight? They ask you for a number of ratings about buying your ticket, attributes of the plane, the service you received, and if you were satisfied, if you wo...

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Bubble Plots (ggplot2)

July 8, 2012
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Bubble Plots (ggplot2)

1 Introduction Rarely have I seen a three dimension graph including time, value, and volatility. It is essenti

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New package RcppCNPy with release 0.1.0 (and 0.0.1 earlier last week)

A few days ago I had blogged about getting NumPy data in R by using a simple converter script. That works fine, but it is a little annoying to have to write an entire file only to read from it again. So I kept looking around for a better solution---and soon found the cnpy library by Carl Rogers which provides simple C++...

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Representation of numerical NA’s in R and the 1954 enigma

July 8, 2012
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Representation of numerical NA’s in R and the 1954 enigma

I've always wondered how exactly the missing value (NA) in R is represented under the hood. Last weekend I was working on a little project that gave me enough excuse to spend some time on finding this out. So, I … Continue reading →

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Fitting a dynamic model, and determining the number of parameters that can be fitted.

July 8, 2012
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Fitting a dynamic model, and determining the number of parameters that can be fitted.

Let's suppose that we have the same dynamic model we presented before - that is, the Lorentz system of differential equations. Remember? In order to perform a fitting we need to define an objective function of sort: this will then be minimised. Now,...

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