oce (version 0.9-14)

plot.landsat: Plot landsat data

Description

Plot landsat data.

Usage

## S3 method for class 'landsat':
plot(x, which=1, band, decimate=1, zlim, col=oceColorsPalette,
    debug=getOption("oceDebug"), ...)

Arguments

x

A landsat object, e.g. as read by read.landsat.

which

desired plot type; 1=image, 2=histogram.

zlim

either a pair of numbers giving the limits for the colourscale, or "histogram" to have a flattened histogram (i.e. to maximally increase contrast throughout the domain.) If not given, the 1 and 99 percent quantiles are calc

col

a function yielding colours, taking a single integer argument with the desired number of colours.

band

if given, the number of the band to plot (between 1 and 11 for Landsat-8). If not given, 8 will be used if band8 exists in the object data, or otherwise the first band will be used.

decimate

decimation interval for images plots; e.g. setting to 10 means to show only every 10-th point in both directions, for a plot simplification by a factor 100. The purpose is mainly to speed up plotting, which can be slow on large landsat

debug

set to a positive value to get debugging information during processing.

...

optional arguments passed to plotting functions.

Details

Since landsat images are very detailed, it is sensible to use a fast plotting device, e.g. x11, and to use perhaps decimate=10 for initial images. The histogram plot can be handy in setting scales, e.g. when an image has a fair bit of land, the histogram will be double-lobed, and so quick examination can help in setting a good value for zlim. Using zlim="histogram" is probably the fastest way to explore an image for detail, but it is important to bear in mind that it yields a nonlinear colourscale.

See Also

The documentation for landsat-class explains the structure of landsat objects, and also outlines the other functions dealing with them. The ocedata package provides a dataset named landsat.

Examples

library(oce)
library(ocedata)
data(landsat)
plot(landsat, which=1, band=8, xlim=c(0.10, 0.15), breaks=200) # suggests z limits
plot(landsat, which=2)
plot(landsat, which=2, zlim=c(0.105, 0.130))
plot(landsat, which=2, zlim="histogram") # ugly but shows details best