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Visualisation shortcuts

iview.Rd

Routines for visualisation of meteogrid objects. They use the meteogrid methods of image, contour, fcontour and vecplot.

Usage

iview(x,nlevels=15,color.palette=irainbow,
      levels=pretty(x[1:gdomain$nx,1:gdomain$ny], nlevels),
      col=color.palette(length(levels)-1),
      title=paste(attr(x,"info")$name,"\n",attr(x,"time")),
      legend=FALSE, mask=NULL, na.col=par("bg"),
      drawmap=TRUE, maplwd=.5, mapcol='black', map.database='world',
      interior=TRUE, fill=FALSE, ...)
cview(x,nlevels=15,
      title=paste(attr(x,"info")$name,"\n",attr(x,"time")),
      mask=NULL, add=FALSE,
      drawmap=!add, maplwd=.5, mapcol="black", map.database="world",
      interior=TRUE, fill=FALSE, ...)
fcview(x,nlevels=15,color.palette=irainbow,
       levels=pretty(x[1:gdomain$nx,1:gdomain$ny], nlevels),
       col=color.palette(length(levels)-1),
       title=paste(attr(x,"info")$name,"\n",attr(x,"time")),
       legend=TRUE,mask=NULL,
       drawmap=TRUE, maplwd=.5, mapcol='black', map.database='world',
      interior=TRUE, fill=FALSE, ...)
vview(U, V, add=FALSE, aspcorrect=TRUE,
      drawmap=TRUE, maplwd=.5, mapcol="black", map.database='world',
      interior=TRUE, fill=FALSE, ...)

Arguments

x

A geofield object.

U,V

geofield objects interpreted as U and V components of a wind field.

nlevels

Number of (colour) levels. You may also give the levels explicitely.

color.palette

Colours for the levels.

levels

A fixed set of breaks. If levels is defined, nlevels is ignored. If missing, the value range is devided in approximately nlevels breaks.

col

A fixed vector of colours. If provided, the length must be exactly equal to length(levels)-1. So it is only practicle to define this if you also have a fixed set of levels.

title

Title for the plot.

add

If TRUE, the plot is superposed on the current image,

mask

Defines a mask such that all grid points with mask==FALSE are set to NA. The mask may be a matrix with the same dimension as x, an expression involving x, or even a string that is parsed and which uses 'x' to represent the data.

na.col

By default, masked grid points (and any other NA values) are transparent. With na.col you can give them another colour.

legend

If TRUE, a color legend is drawn at the right of the image.

drawmap

If TRUE, a world map is superposed on the image.

fill

If TRUE, the map is drawn as filled polygons, not just lines. This is most interesting for contours and vectors, but may in rare cases be used with images, if the colours are transparent.

interior

If FALSE, the interior political borders are not drawn.

maplwd, mapcol

Line width and colour for the world map.

map.database

Which map data to use. Default is 'world' from the maps package.

aspcorrect

In Lat/Lon co-ordinates, the aspect ratio is not 1:1. If this argument is TRUE, a correction is attempted. For other projections, this argument is ignored.

...

Further options for limage, vecplot or contour.

Value

An image (iview), contour (cview) or filled contour (fcview) plot of the data, overlaid by geographical boundaries. vview plots a vector field (e.g. wind).

Details

These functions are in fact simple "wrappers" for the more general functions limage etc. The (...) indicates any parameter that is accepted by these functions.

See also

limage,vecplot,contour

Examples

if (FALSE) {
# mask as a string that is evaluated literally (x is the input data)
iview(x=field,mask="x>0") # all negative values are left blank
# mask as an expression, assuming lsm is a known geofield
iview(x=field,mask=lsm) # all points where lsm=FALSE are left blank
}