3090 search results for "GIS"

Scenario analysis for option strategies Pt. 2

June 10, 2013
By

No vivid improvements since the last post. However, I got it to the stage, when I can share the code and let you try it yourself: https://github.com/afraid2trade/SCENARIO_ANALYSIS.git Once you downloaded it, the only thing you need to open is "sa_work...

Read more »

Microsoft Office Metadata with R

June 10, 2013
By

Sometimes I need to retrieve various items of metadata from Microsoft Office files. For the 'old-style' (i.e. '.doc' and '.xls') files perhaps a solution in python, such as hachoir, was the best way to extract this data from the ole2 file format -...

Read more »

The RStudio CRAN mirror

June 10, 2013
By
The RStudio CRAN mirror

RStudio maintains its own CRAN mirror, http://cran.rstudio.com. The server itself is a virtual machine run by Amazon’s EC2 service, and it syncs with the main CRAN mirror in Austria once per day. When you contact http://cran.rstudio.com, however, you’re probably not talking to our CRAN mirror directly. That’s because we use Amazon CloudFront, a content delivery

Read more »

Measure of Relative Variability

June 10, 2013
By

The measure of relative variability is the coefficient of variation (CV). Unlike measures of absolute variability, the CV is unitless when it comes to comparisons between the dispersions of two distributions of different units of measurement. In R, CV ...

Read more »

Measures of Absolute Variability

June 10, 2013
By

Measures of absolute variability deal with the dispersion of the data points. This include the following:Range - rangeInterquartile Range - IQRQuartile DeviationAverage DeviationStandard Deviation - sdThese measures of variability restrict to uniform u...

Read more »

Why are Birds Dinosaurs?

June 9, 2013
By
Why are Birds Dinosaurs?

Month after month, one of the most popular posts on the Paleocave blog is the How to Read a Cladogram post I did some time ago. I always intended to follow it up with more cladistic fun. So, hold onto your butts, we’re going to let the dinosaurs loose. Birds are dinosaurs. We’ve all heard

Read more »

Quartiles, Deciles, and Percentiles

June 9, 2013
By

The measures of position such as quartiles, deciles, and percentiles are available in quantile function. This function has a usage,where:x - the data pointsprob - the location to measurena.rm - if FALSE, NA (Not Available) data points are not ignoredna...

Read more »

Quick and Simple D3 Network Graphs from R

June 8, 2013
By
Quick and Simple D3 Network Graphs from R

Sometimes I just want to quickly make a simple D3 JavaScript directed network graph with data in R. Because D3 network graphs can be manipulated in the browser–i.e. nodes can be moved around and highlighted–they're really nice for data exploration. They're also really nice in HTML presentations. So I put together a...

Read more »

Mean and Median

June 8, 2013
By

Mean in R is computed using the function mean. Consider the scores of 20 MSU-IIT students in Stat 101 exam with a hundred items: 70, 78, 66, 65, 50, 53, 48, 88, 95, 80, 85, 84, 81, 63, 68, 73, 75, 84, 49, and 77. Compute and interpret the mean and medi...

Read more »

Matrix Operations

June 8, 2013
By

Matrix manipulation in R are very useful in Linear Algebra. Below are lists of common yet important functions in dealing operations with matrices:Transpose - tMultiplication - %*%Determinant - detInverse - solve, or ginv of MASS libraryEigenvalues and ...

Read more »