crop {satin} | R Documentation |
Cut a satin object
Description
Select and cut a polygon shaped area of interest from a satin object.
Usage
crop(X, polygon = NULL, return.poly = FALSE)
Arguments
X |
a satin object as returned by |
polygon |
a polygon defining the area of interest (aoi) to be cutted. |
return.poly |
if TRUE, |
Details
If provided, the polygon defining the aoi must have two columns with x and y coordinates. The function verifies that the last point is exactly the same as the first one. When not specified, the user can draw a polygon by clicking on a previously displayed image. Note that for drawing the polygon in this manner, the plot of the satin object has to be created using colbar = FALSE
. The result is a satin object where the pixels outside the aoi are set to NA. In order to cut Copernicus data returned from read.cmems
, the appropriate indexing should be previously done.
Value
A cutted satin object.
When return.poly = TRUE
, a list with two components:
aoi |
cutted satin object. |
polygon |
polygon coordinates defining the aoi. |
Author(s)
Héctor Villalobos
See Also
Examples
# load and display sample data
data(dsst)
plot(dsst)
# define polygon, cut the image and display the aoi
polyg <- data.frame(x = c(-110, -105, -113, -116, -110), y = c(23, 23, 32, 32, 23))
dsst.clip <- crop(dsst, polygon = polyg)
plot(dsst.clip)
if(interactive()){
# the same, but polygon is defined by clicking on the image
plot(dsst, colbar = FALSE)
dsst.clip2 <- crop(dsst, return.poly = TRUE) # *** draw the aoi polygon ***
dsst.clip2$polygon # show polygon coordinates
plot(dsst.clip2$aoi) # plot the selected aoi
}