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Last data update: 2014.03.03

R: Tiles (subsets or clips) a spatial object to regular blocks

tile	R Documentation

Tiles (subsets or clips) a spatial object to regular blocks

Description

Tiles objects of class "Spatial*" or "RasterLayer*" into regular blocks.

Usage

## S4 method for signature 'SpatialPointsDataFrame'
tile(x, y, block.x, ...)
## S4 method for signature 'SpatialPixelsDataFrame'
tile(x, y, block.x, ...)
## S4 method for signature 'SpatialPolygonsDataFrame'
tile(x, y, block.x, tmp.file = TRUE, 
    program, show.output.on.console = FALSE, ...)
## S4 method for signature 'SpatialLinesDataFrame'
tile(x, y, block.x, tmp.file = TRUE, 
    program, show.output.on.console = FALSE, ...)
## S4 method for signature 'RasterLayer'
tile(x, y, block.x, tmp.file = TRUE, 
    program, show.output.on.console = FALSE, ...)

Arguments

`x`	object of class `"Spatial*"` `"RasterLayer"`
`y`	list of `"SpatialPolygons"`; if missing will be derived based on `block.x`
`block.x`	numeric; size of block in meters or corresponding mapping units
`tmp.file`	logical; specifies whether to generate a temporary file
`program`	character; location of the auxiliary program in the system
`show.output.on.console`	logical; specifies whether to print the progress of a function
`...`	optional arguments that can be passed to the `getSpatialTiles`

Details

When working with objects of type "SpatialLinesDataFrame", "SpatialPolygonsDataFrame" and or "RasterLayer", the function looks for FWTools binary files ogr2ogr and warp. FWTools is a separate program and must be installed separately.

Value

Returns a list of objects of the same class as the input object.

Author(s)

Tomislav Hengl

Examples

## spatial pixels:
library(sp)
data(meuse.grid)
gridded(meuse.grid) <- ~x+y
tl <- getSpatialTiles(meuse.grid, block.x=1000)
image(meuse.grid)
lines(as(tl, "SpatialLines"))
## all at once:
pix.lst <- tile(meuse.grid, block.x=1000)
## Not run: ## lines:
library(plotKML)
data(eberg_contours)
line.lst <- tile(eberg_contours, block.x=5000)
spplot(line.lst[[1]][2])
## polygons:
data(eberg_zones)
## this one requires ogr2ogr function:
pol.lst <- tile(eberg_zones, block.x=5000)
spplot(pol.lst[[1]][1])
## raster files via rgdal:
library(rgdal)
fn = system.file("pictures/SP27GTIF.TIF", 
 package = "rgdal")
obj <- GDALinfo(fn)
ras.lst <- getSpatialTiles(obj, block.x=1000)
offset <- c(ras.lst$offset.y[1], ras.lst$offset.x[1])
region.dim <- c(ras.lst$region.dim.y[1], 
  ras.lst$region.dim.x[1])
## read the first tile:
SP27GTIF_T1 <- readGDAL(fn, offset=offset, 
  region.dim=region.dim)
str(SP27GTIF_T1)

## End(Not run)

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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> library(GSIF)
GSIF version 0.5-2 (2016-06-25)
URL: http://gsif.r-forge.r-project.org/
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/GSIF/tile.Rd_%03d_medium.png", width=480, height=480)
> ### Name: tile
> ### Title: Tiles (subsets or clips) a spatial object to regular blocks
> ### Aliases: tile tile,SpatialPixelsDataFrame-method
> ###   tile,SpatialPointsDataFrame-method tile,SpatialLinesDataFrame-method
> ###   tile,SpatialPolygonsDataFrame-method tile,RasterLayer-method
> ### Keywords: methods
> 
> ### ** Examples
> 
> ## spatial pixels:
> library(sp)
> data(meuse.grid)
> gridded(meuse.grid) <- ~x+y
> tl <- getSpatialTiles(meuse.grid, block.x=1000)
Generating 20 tiles...
Returning a list of tiles for an object of class SpatialPixelsDataFrame with 0 percent overlap
> image(meuse.grid)
> lines(as(tl, "SpatialLines"))
> ## all at once:
> pix.lst <- tile(meuse.grid, block.x=1000)
Generating 20 tiles...
Returning a list of tiles for an object of class SpatialPixelsDataFrame with 0 percent overlap
Subseting object of class "SpatialPixelsDataFrame"...
> ## Not run: 
> ##D ## lines:
> ##D library(plotKML)
> ##D data(eberg_contours)
> ##D line.lst <- tile(eberg_contours, block.x=5000)
> ##D spplot(line.lst[[1]][2])
> ##D ## polygons:
> ##D data(eberg_zones)
> ##D ## this one requires ogr2ogr function:
> ##D pol.lst <- tile(eberg_zones, block.x=5000)
> ##D spplot(pol.lst[[1]][1])
> ##D ## raster files via rgdal:
> ##D library(rgdal)
> ##D fn = system.file("pictures/SP27GTIF.TIF", 
> ##D  package = "rgdal")
> ##D obj <- GDALinfo(fn)
> ##D ras.lst <- getSpatialTiles(obj, block.x=1000)
> ##D offset <- c(ras.lst$offset.y[1], ras.lst$offset.x[1])
> ##D region.dim <- c(ras.lst$region.dim.y[1], 
> ##D   ras.lst$region.dim.x[1])
> ##D ## read the first tile:
> ##D SP27GTIF_T1 <- readGDAL(fn, offset=offset, 
> ##D   region.dim=region.dim)
> ##D str(SP27GTIF_T1)
> ## End(Not run)
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>