[R] Generating kml lines output

[Barry Rowlingson]

On Fri, Nov 26, 2010 at 5:03 PM, fbielejec <fbielejec at gmail.com> wrote:
> Dear,
>
> I would like to generate kml file with lines (<LineString>) of
> different style (definitely color, but width would also be nice to
> see). However with kmlLine from maptools package I am able only to
> output the single first Lines object (first row of
> SpatialLinesDataFrame)
>
> I guess the option would be to have single Lines object (instead of
> list of them), but then also the style wouldn't vary among them... My
> code so far:

 If you cant get what you want from package code, and you know a bit
about the KML format you are trying to produce, then try using the R
'brew' package, which lets your write a template which can have loops,
variable substitutions, and other bits of R code in it.

 For example, here creating a simple set of KML points from a data
frame called 'cpts':

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.1">
<Document>
<% for(i in 1:nrow(cpts)){ %>
<Placemark>
<Name><%=paste("pt-",i,sep="")%></Name>
<Point>
<coordinates><%=cpts[i,]$Xt%>,<%=cpts[i,]$Yt%>,0</coordinates>
</Point>
</Placemark>
<% } %>
</Document>
</kml>


results in a KML with lots of these:

<Placemark>
<Name>pt-4</Name>
<Point>
<coordinates>-43.93769,-19.92065,0</coordinates>
</Point>
</Placemark>

 - its a lot easier than writing lots of cat() and other formatting
nonsense in R code!

 But if you can get package code to do it, that's the way to go. But
for outside-the-box solutions, install.packages("brew")!

Barry