plotKML: layer.SpatialPoints – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

layer.SpatialPoints

Writes spatial points to KML

Description

Writes object of class "SpatialPoints*" to KML with a possibility to parse attribute variables using several aesthetics arguments.

Usage

kml_layer.SpatialPoints(obj, subfolder.name = paste(class(obj)), 
        extrude = TRUE, z.scale = 1, 
        LabelScale = get("LabelScale", envir = plotKML.opts), 
        metadata = NULL, html.table = NULL, TimeSpan.begin = "",
        TimeSpan.end = "", points_names, ...)

Arguments

`obj`	object of class `"SpatialPoints*"`
`subfolder.name`	character; optional subfolder name
`extrude`	logical; specifies whether to connect the point to the ground with a line
`z.scale`	numeric; exaggeration in vertical dimension
`LabelScale`	numeric; scale factor for size of labels
`metadata`	(optional) specify the metadata object
`html.table`	(optional) specify the description block (html) for each point
`TimeSpan.begin`	(optional) beginning of the referent time period
`TimeSpan.end`	(optional) end of the referent time period
`points_names`	character; forces the point labels (size of the character vector must equal the number of the points)
`...`	additional style arguments (see `aesthetics`)

Details

TimeSpan.begin and TimeSpan.end are optional TimeStamp vectors:

yyyy-mm-ddThh:mm:sszzzzzz

For observations at point support (a single moment in time), use the same time values for both TimeSpan.begin and TimeSpan.end. TimeSpan.begin and TimeSpan.end can be either a single value or a vector of values.
Optional aesthetics arguments are shapes (icons), colour, sizes, altitude (if not a 3D object; variable to be used to specify altitude above ground), altitudeMode (altitude mode type (clampToGround, relativeToGround or absolute). Although this function can be used to plot over five variables, more than three aesthetics arguments is not recommended (e.g. limit to size and colour).

Author(s)

Pierre Roudier, Tomislav Hengl and Dylan Beaudette

Examples

data(eberg)
data(SAGA_pal)
library(sp)
library(rgdal)
coordinates(eberg) <- ~X+Y
proj4string(eberg) <- CRS("+init=epsg:31467")
names(eberg)
# subset to 10 percent:
eberg <- eberg[runif(nrow(eberg))<.1,]
## Not run: # plot the measured CLAY content:
kml(eberg, labels = CLYMHT_A)
shape = "http://maps.google.com/mapfiles/kml/pal2/icon18.png"
# color only:
kml(eberg, shape = shape, colour = SLTMHT_A, labels = "", colour_scale = SAGA_pal[[1]])
# two variables at the same time:
kml(eberg, shape = shape, size = CLYMHT_A, colour = SLTMHT_A, labels = "")
# two aesthetics elements are effective in emphasizing hot-spots:
kml(eberg, shape = shape, altitude = CLYMHT_A*10, extrude = TRUE, 
  colour = CLYMHT_A, labels = CLYMHT_A, kmz = TRUE)

## End(Not run)

## example of how plotKML is programmed:
data(HRtemp08)
HRtemp08[1,]
library(XML)
p1 = newXMLNode("Placemark")
begin <- format(HRtemp08[1,"DATE"]-.5, "%Y-%m-%dT%H:%M:%SZ")
end <- format(HRtemp08[1,"DATE"]+.5, "%Y-%m-%dT%H:%M:%SZ")
txt <- sprintf('<name>%s</name><TimeStamp><begin>%s</begin><end>%s</end></TimeStamp>
    <Point><coordinates>%.4f,%.4f,%.0f</coordinates></Point>', HRtemp08[1,"NAME"], 
    begin, end, HRtemp08[1,"Lon"], HRtemp08[1,"Lat"], 0)
parseXMLAndAdd(txt, parent=p1)
p1

plotKML

Visualization of Spatial and Spatio-Temporal Objects in Google Earth

v0.8-1

GPL

Authors

Tomislav Hengl [cre, aut], Andrea Gilardi [ctb], Pierre Roudier [ctb], Dylan Beaudette [ctb], Edzer Pebesma [ctb], Michael Blaschek [ctb]

Initial release

2021-04-12