R script to create QGIS legend file (qml)

#!/usr/bin/env Rscript

# R Script R to create Quantum GIS legend file from table -----------
# create .qml file from a table with RGB values
# Source: http://pvanb.wordpress.com
# Blog entries: http://bit.ly/1pXVlJJ http://bit.ly/1wET222


# Libraries --------------------------------------------------------
library(brew)

# Set workspace from script is runnning (on Linux)
setwd(system("pwd", intern = TRUE))

# Import table -----------------------------------------------------
legend_table <- read.csv("./files/legend_table.csv")

# Create XML file - qml file ---------------------------------------
xml.out <- file(paste(getwd(), "/", "QGIS_template.qml", sep=""),"w")


# Set parameters ---------------------------------------------------

# Names of the columns from the attribute table used to create the style file
Link <- "ID2"         # campo ID2
Label <- "NAME"       # Country name
ColorFill <- "RGB"    # Column with color code (R:G:B)

# Create vectors with unique value, label and colour values
Value <- legend_table[,Link]
legend_table <- legend_table[!duplicated(Value),]
Value <- legend_table[,Link] # I'm not really understand this steps ¿?
Label <- legend_table[,Label]  # Is it not the same as Label <- legend_table$NAME ??
ColorFill <- legend_table[,ColorFill] # Is it not the same as ColorFill <- legend_table$RGB ??

# Symbol parameters
ColorBorder <- "0,0,0,255"
FillStyle <- "solid"
BorderStyle <- "no"
BorderWidth <- "0.2"


# Write header information to the style file --------------------------------

brew(text=paste("<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
<qgis version=\"2.4.0-Chugiak\" minimumScale=\"0\" maximumScale=\"1e+08\" hasScaleBasedVisibilityFlag=\"0\">
<transparencyLevelInt>255</transparencyLevelInt>
<renderer-v2 attr=\"<%=Link%>\" symbollevels=\"0\" type=\"categorizedSymbol\">", sep=""), output=xml.out)


# Write the categories definitions to the style file -------------------------

# Write start line <categories>

brew(text=paste("<categories>
<%-%>", sep=""), output=xml.out)

# Write categories with

for(i in 1:dim(legend_table)[1]){
  Value2 <- Value[i]
  Label2 <- as.character(Label[i]) # added (from original code) to transform to character type
  brew(text=paste("<category symbol=\"<%=i%>\" value=\"<%=Value2%>\" label=\"<%=Label2%>\"/>
<%-%>", sep=""), output=xml.out)
}

# Write end lines </categories> \n <symbols>

brew(text=paste("</categories>
<symbols>
<%-%>", sep=""), output=xml.out)


# Write the style definitions to the style file --------------------------------

for(i in 1:dim(legend_table)[1]){
  Value2 <- Value[i]
  ColorFill2 <- gsub(":",",", ColorFill[i],)
  brew(text=paste("<symbol outputUnit=\"MM\" alpha=\"1\" type=\"fill\" name=\"<%=i%>\">
<layer pass=\"0\" class=\"SimpleFill\" locked=\"0\">
<prop k=\"color\" v=\"<%=ColorFill2%>\"/>
<prop k=\"color_border\" v=\"<%=ColorBorder%>\"/>
<prop k=\"offset\" v=\"0,0\"/>
<prop k=\"style\" v=\"<%=FillStyle%>\"/>
<prop k=\"style_border\" v=\"<%=BorderStyle%>\"/>
<prop k=\"width_border\" v=\"<%=BorderWidth%>\"/>
</layer>
</symbol>
<%-%>", sep=""), output=xml.out)
}

# Write closing lines to the footer -----------------------------------------

brew(text=paste("</symbols>
</renderer-v2>
</qgis>", sep=""), output=xml.out)

# It works!! :D