Create a proxy data cube, which extracts a time slice from a data cube defined by label (datetime string) or integer index.
Usage
slice_time(cube, datetime =NULL, it =NULL)
Arguments
Argument
Description
cube
source data cube
datetime
character; datetime string of the time slice
it
integer; index of the time slice (zero-based)
Details
Either datetime or it must be non-NULL. If both arguments are provided, the integer index it is ignored.
Note
This function returns a proxy object, i.e., it will not start any computations besides deriving the shape of the result.
Examples
# create image collection from example Landsat data only # if not already done in other examplesif (!file.exists(file.path(tempdir(), "L8.db"))) { L8_files <-list.files(system.file("L8NY18", package ="gdalcubes"),".TIF", recursive =TRUE, full.names =TRUE)create_image_collection(L8_files, "L8_L1TP", file.path(tempdir(), "L8.db"), quiet =TRUE) }L8.col =image_collection(file.path(tempdir(), "L8.db"))v =cube_view(extent=list(left=388941.2, right=766552.4, bottom=4345299, top=4744931, t0="2018-01", t1="2018-12"),srs="EPSG:32618", nx =497, ny=526, dt="P1M", aggregation ="median")L8.cube =raster_cube(L8.col, v, mask=image_mask("BQA", bits=4, values=16))L8.rgb =select_bands(L8.cube, c("B02", "B03", "B04"))L8.slice =slice_time(L8.rgb, "2018-03")L8.slice
A data cube proxy object
Dimensions:
low high count pixel_size chunk_size
t 2018-03-01 2018-03-31 1 P1M 1
y 4345299 4744931 526 759.756653992395 384
x 388941.2 766552.4 497 759.781086519115 384
Bands:
name offset scale nodata unit
1 B02 0 1 NaN
2 B03 0 1 NaN
3 B04 0 1 NaN
plot(L8.slice, rgb=3:1, zlim=c(5000,12000))
Source Code
# slice_timeExtract a single time slice from a data cube```{r include=FALSE}library(gdalcubes)```## DescriptionCreate a proxy data cube, which extracts a time slice from a data cube defined by label (datetime string) or integer index.## Usage```rslice_time(cube, datetime =NULL, it =NULL)```## Arguments| Argument | Description ||:------------|:----------------------------------|| cube | source data cube || datetime | character; datetime string of the time slice || it | integer; index of the time slice (zero-based) |## DetailsEither `datetime` or `it` must be non-NULL. If both arguments are provided, the integer index `it` is ignored.## NoteThis function returns a proxy object, i.e., it will not start any computations besides deriving the shape of the result.## Examples```{r}# create image collection from example Landsat data only # if not already done in other examplesif (!file.exists(file.path(tempdir(), "L8.db"))) { L8_files <-list.files(system.file("L8NY18", package ="gdalcubes"),".TIF", recursive =TRUE, full.names =TRUE)create_image_collection(L8_files, "L8_L1TP", file.path(tempdir(), "L8.db"), quiet =TRUE) }L8.col =image_collection(file.path(tempdir(), "L8.db"))v =cube_view(extent=list(left=388941.2, right=766552.4, bottom=4345299, top=4744931, t0="2018-01", t1="2018-12"),srs="EPSG:32618", nx =497, ny=526, dt="P1M", aggregation ="median")L8.cube =raster_cube(L8.col, v, mask=image_mask("BQA", bits=4, values=16))L8.rgb =select_bands(L8.cube, c("B02", "B03", "B04"))L8.slice =slice_time(L8.rgb, "2018-03")L8.sliceplot(L8.slice, rgb=3:1, zlim=c(5000,12000))```
