slideView {slideview} | R Documentation |
slideView
Description
Two images are overlaid and a slider is provided to interactively
compare the two images in a before-after like fashion. img1
and
img2
can either be two RasterLayers, two RasterBricks/Stacks or
two character strings. In the latter case it is assumed that these
point to .png images on the disk.
NOTE: In case you want to include multiple slideviews in one page in a Rmd or flexdashboard we highly recommend using package widgetframe. Also, make sure to use different image names and/or labels for each of the RasterLayers/Bricks/Stacks. Otherwise things will likely not work properly.
This is a modified implementation of http://bl.ocks.org/rfriberg/8327361
Usage
## S4 method for signature 'RasterStackBrick,RasterStackBrick'
slideView(
img1,
img2,
label1 = deparse(substitute(img1, env = parent.frame())),
label2 = deparse(substitute(img2, env = parent.frame())),
r = 3,
g = 2,
b = 1,
na.color = "#BEBEBE",
maxpixels = 1e+07,
...
)
## S4 method for signature 'RasterLayer,RasterLayer'
slideView(
img1,
img2,
label1 = deparse(substitute(img1, env = parent.frame())),
label2 = deparse(substitute(img2, env = parent.frame())),
legend = TRUE,
col.regions = viridisLite::inferno(256),
na.color = "#BEBEBE",
maxpixels = 1e+07
)
## S4 method for signature 'RasterStackBrick,RasterLayer'
slideView(
img1,
img2,
label1 = deparse(substitute(img1, env = parent.frame())),
label2 = deparse(substitute(img2, env = parent.frame())),
legend = TRUE,
r = 3,
g = 2,
b = 1,
col.regions = viridisLite::inferno(256),
na.color = "#BEBEBE",
maxpixels = 1e+07,
...
)
## S4 method for signature 'RasterLayer,RasterStackBrick'
slideView(
img1,
img2,
label1 = deparse(substitute(img1, env = parent.frame())),
label2 = deparse(substitute(img2, env = parent.frame())),
legend = TRUE,
r = 3,
g = 2,
b = 1,
col.regions = viridisLite::inferno(256),
na.color = "#BEBEBE",
maxpixels = 1e+07,
...
)
## S4 method for signature 'character,character'
slideView(
img1,
img2,
label1 = deparse(substitute(img1, env = parent.frame())),
label2 = deparse(substitute(img2, env = parent.frame()))
)
## S4 method for signature 'ANY'
slideview(...)
Arguments
img1 |
a RasterStack/Brick, RasterLayer or path to a .png file |
img2 |
a RasterStack/Brick, RasterLayer or path to a .png file |
label1 |
slider label for img1 (defaults to object name) |
label2 |
slider label for img2 (defaults to object name) |
r |
integer. Index of the Red channel, between 1 and nlayers(x) |
g |
integer. Index of the Green channel, between 1 and nlayers(x) |
b |
integer. Index of the Blue channel, between 1 and nlayers(x) |
na.color |
the color to be used for NA pixels |
maxpixels |
integer > 0. Maximum number of cells to use for the plot.
If maxpixels < |
... |
additional arguments passed on to repective functions. |
legend |
whether to plot legends for the two images (ignored for RatserStacks/*Bricks). |
col.regions |
color (palette).See |
color |
the color palette to be used for visualising RasterLayers |
Details
Compare two images trough interactive swiping overlay
For slideView there are a few keyboard shortcuts defined:
space - toggle antialiasing
esc - zoom to layer extent
enter - set zoom to 1
ctrl - increase panning speed by 10
Methods (by class)
-
img1 = RasterLayer,img2 = RasterLayer
: for RasterLayers -
img1 = RasterStackBrick,img2 = RasterLayer
: for RasterStackBrick, RasterLayer -
img1 = RasterLayer,img2 = RasterStackBrick
: for RasterLayer, RasterStackBrick -
img1 = character,img2 = character
: for png files -
ANY
: alias for ease of typing
Author(s)
Tim Appelhans
Stephan Woellauer
Examples
if (interactive()) {
### example taken from
### http://www.news.com.au/technology/environment/nasa-images-reveal-
### aral-sea-is-shrinking-before-our-eyes/story-e6frflp0-1227074133835
library(jpeg)
library(raster)
web_img2000 <- "http://cdn.newsapi.com.au/image/v1/68565a36c0fccb1bc43c09d96e8fb029"
jpg2000 <- readJPEG(readBin(web_img2000, "raw", 1e6))
# Convert imagedata to raster
rst_blue2000 <- raster(jpg2000[, , 1])
rst_green2000 <- raster(jpg2000[, , 2])
rst_red2000 <- raster(jpg2000[, , 3])
img2000 <- brick(rst_red2000, rst_green2000, rst_blue2000)
web_img2013 <- "http://cdn.newsapi.com.au/image/v1/5707499d769db4b8ec76e8df61933f2a"
jpg2013 <- readJPEG(readBin(web_img2013, "raw", 1e6))
# Convert imagedata to raster
rst_blue2013 <- raster(jpg2013[, , 1])
rst_green2013 <- raster(jpg2013[, , 2])
rst_red2013 <- raster(jpg2013[, , 3])
img2013 <- brick(rst_red2013, rst_green2013, rst_blue2013)
slideView(img2000, img2013, label1 = "before", label2 = "after")
}