kmlPolygons
Create and write a KML file on the basis of a given Polygons object or list of Polygons or SpatialPolygonsDataFrame
The function is used to create and write a KML file on the basis of a given Polygons object (a list of Polygon objects of SpatialPolygonsDataFrame class) for the usage in Google Earth and Google Maps.
- Keywords
- spatial
Usage
kmlPolygons(obj=NULL, kmlfile=NULL,
name="KML Polygons", description="", col=NULL, visibility=1, lwd=1,
border="white", kmlname="", kmldescription="")Arguments
- obj
a
PolygonsorSpatialPolygonsDataFrameobject or list of objects- kmlfile
if not
NULLthe name as character string of the kml file to be written to working directory as "NAME.kml"- name
the name of the KML polygon in Google Earth
- description
the description of the KML polygon displayed in Google Earth or Maps (HTML tags allowed)
- col
the fill color (see also Color Specification) of the KML polygon. If passing a list of
PolyonsorSpatialPolygonsDataFrameandlength(col)is less thanlength(object)the first color in col will be applied to all objects in the list- visibility
if set to
1orTRUEspecifies that the KML polygon should be visible after loading- lwd
the stroke (polygon's border line) width for the KML polygon
- border
the stroke color (see also Color Specification) for the KML polygon
- kmlname
the name of the KML layer
- kmldescription
the description of the KML layer (HTML tags allowed)
Details
The function is used to convert a given Polygons object (a list of Polygon objects) or the Polygons object listed in a passed SpatialPolygonsDataFrame object into KML polygon. If kmlfile is not NULL the result will be written into that file. If kmlfile is NULL the generated KML lines will be returned (see also value).
The conversion can also handle polygons which are marked as holes inside of the Polygons object if these holes are listed right after that polygon in which these holes appear. That implies that a given plot order set in the Polygons object will not be considered.
For a passed Polygons object the function generates a <Style> tag whereby its id attribute is set to the passed object's ID.
Note that the geometries should be in geographical coordinates with datum WGS84.
The resulting KML polygon will be embedded in <Placemark><MultiGeometry><Polygon>.
Value
x is a list with the elements style and content containing the generated lines of the KML file as character vectors if kmlfile is NULL.
y is a list with the elements header and footer representing the KML file' header resp. footer if obj is NULL (see second example).
Color Specification
The following color specifications are allowed: 'red', 2, or as hex code '#RRGGBB' resp. '#RRGGBBAA' for passing the alpha value.
See Also
kmlPolygon, kmlLines, SpatialPolygons, kmlPoints
Examples
# NOT RUN {
data(wrld_simpl)
td <- tempdir()
kmlfile <- paste(td, "worldPolitical.kml", sep="/")
## creates a KML file containing the polygons of a political world map
kmlPolygons(wrld_simpl, kmlfile = kmlfile, name = "KML Polygons",
description = "the world", col = "red",
visibility = 1, lwd = 1, border = "white", kmlname = "R Test",
kmldescription = "This is <b>only</b> a <a href='http://www.r-project.org'>R</a> test.")
data(wrld_simpl)
## create a KML file containing the polygons of Brazil, Uganda, and Canada
regions <- c("Brazil","Canada","Uganda")
wrld_simpl_subset <- wrld_simpl[wrld_simpl$NAME %in% regions,]
kmlfile <- paste(td, "worldPoliticalSubset.kml", sep="/")
kmlPolygons(wrld_simpl_subset, kmlfile = kmlfile,
name = "KML Polygons subset", description = "three countries", col = "blue",
visibility = 1, lwd = 1, border = "white", kmlname = "R Test 2",
kmldescription = "This is <b>only</b> a <a href='http://www.r-project.org'>R</a> test.")
## combine to make a list of polygon objects to plot
polList <- c(regions,wrld_simpl)
kmlfile <- paste(td, "worldPoliticalandSubset.kml", sep="/")
kmlPolygons(wrld_simpl_subset, kmlfile = kmlfile,
name = "KML Polygons subset", description = "three countries highlighted in world",
col = sample(colours(), length(polList)), visibility = 1, lwd = 1, border = "white",
kmlname = "R Test 2",
kmldescription = "This is <b>only</b> a <a href='http://www.r-project.org'>R</a> test.")
# }