First steps in QGIS (including installation on OS X)

Last week I visited a geo data talk at Linuxwochen Linz which was mainly about the tool QGIS. The talk was held by two guys who also write this blog. I am planning to work more with geo data in the future so I installed QGIS and tried a simple example. Installation on OS X … Continue reading First steps in QGIS (including installation on OS X)

[Dimensionality Reduction #2] Understanding Factor Analysis using R

This time I am going to show you how to perform Factor analysis. In the next post I will show you some scaling and projection methods. The idea for this mini-series was inspired by a Machine Learning (Unsupervised) lecture I had at university. I will perform all this methods on the same data sets and … Continue reading [Dimensionality Reduction #2] Understanding Factor Analysis using R

[Dimensionality Reduction #1] Understanding PCA and ICA using R

This time I am going to show you how to perform PCA and ICA. In the next one or two posts I will show you Factor Analysis and some scaling and projection methods. The idea for this mini-series was inspired by a Machine Learning (Unsupervised) lecture I had at university. I will perform all this … Continue reading [Dimensionality Reduction #1] Understanding PCA and ICA using R

Basic handling of spatial data (like GPS coordinates)

This week I am going to show you some very basic things you can do with GPS coordinates. In this post you will learn how to: Read gpx files Read files containing plain text coordinates (like N 48 12.123 and N 48 12′ 123″) Parse characters string that contain unformatted coordinates (like above) Convert minute … Continue reading Basic handling of spatial data (like GPS coordinates)

How to choose the correct plot for your data

Today I am going to talk about how to choose the correct representation for several types of data. From statistics class you might remember there are three types of data: Metric (data can be measured or counted, mathematical operations make sense) Ordinal (data can be ordered in a meaningful way, but mathematical operations (+, -, … Continue reading How to choose the correct plot for your data

How to handle factors in R

Many people seem to have a problem with factors. This might be because factors do not always behave like you expect them to. Factors are vector like objects, but the items can only take certain values. This post gives a very basic introduction to factors. Introduction and usage Factors can be created from vectors. chr.v … Continue reading How to handle factors in R

Info graphic for R plotting parameters

Do you always have to look up the numbers of plotting symbols or lines? I do and that is why I created an info graphic that summarizes these parameters and also some color functions. You can download this graphic here. The numbers on the axes give the value used for pch and lty according to … Continue reading Info graphic for R plotting parameters

Create boxplots in R

My favorite plots are boxplots, because you have a lot of information in them. If you look at a very basic boxplot, you can see the median (bold line), the quartiles (upper and lower boundary of the box) and if there are outliers (by default those are values that are 1.5 times the boxlength away … Continue reading Create boxplots in R