DATA MINING Desktop Survival Guide by Graham Williams
Desktop Survival Project Home List of Figures List of Tables Data Mining Data Mining Data Mining with Rattle Introduction Data Transform Explore A Model Building Framework Unsupervised Modelling Two Class Models Multi Class Models Regression Models Text Mining Evaluation and Deployment Moving into R Troubleshooting R for the Data Miner R Data Graphics in R Understanding Data Preparing Data Building Models Evaluating Models Algorithms Apriori Bagging Bayes Classifier Boosting Cluster Analysis Conditional Trees Hierarchical Clustering K-Means K-Nearest Neighbours Linear Models Logistic Regression Neural Networks Support Vector Machines Text Mining Open Products AlphaMiner Borgelt Data Mining Suite KNime R Rattle Weka Closed Products C4.5 Clementine Equbits Foresight GhostMiner InductionEngine ODM Enterprise Miner Statistica Data Miner TreeNet Virtual Predict Appendicies Glossary Bibliography Index

Global Positioning System

In some situations in analysing data you may actually be collecting the data directly for analysis by R from some external device, possibly connected through the computer's serial port. One such example is using a global positioning system. On a GNU/Linux system this might be connected to your serial device and in R (after ensuring you have read access to the serial port /dev/ttyS0) you can read your current position.

> gps <- scan(file="/dev/ttyS0", n=1, what="character")
Read 1 items
> gps
[1] "@051226122125S0341825E01500808G006+00350E0000N0000D0000"

> columns <- c("tag", "date", "time", "latitude", "longitude",
               "quality", "level", "movelong", "movelat", "movevert")
> widths <- c(1, 6, 6, 8, 9, 4, 6, 5, 5, 5)
> gps.data <- read.fwf("/dev/ttyS0", widths, col.names=columns, n=1,
                       colClasses="character")
> gps.data
  tag   date   time latitude longitude quality  level movelong movelat movevert
1   @ 050221 122125 S0341825 E01500808    G006 +00350    E0000   N0000    D0000

This tells me that the location is 34degrees, 18.25minutes south, 150degrees, 8.08minutes east. The quality is good with a 6meter positional error. This is 35m above sea level, and not moving.

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