getTile: Get MODIS tile id(s)

In MODIS: MODIS Acquisition and Processing

Description

Get MODIS tile id(s) for a geographic area.

Usage

getTile(extent=NULL, tileH=NULL, tileV=NULL, buffer=NULL, system="MODIS", zoom=TRUE)

Arguments

tileH	Integer. Horizontal tile number(s) (between 0 and 35). I.e.: tileH = 19:25
tileV	Integer. Vertical tile number(s) (between 0 and 17). I.e.: tileV = 9:12.
extent	Extent Informations see details.
buffer	Numeric [map units]. Buffers the extent, negative values are allowed. If extent is a vector object ("shp" or _"character"_ name of a "map" object) only 1 value is allowed i.e. buffer=0.5 (rgeos:::gBuffer() is used). In the other cases also buffer=c(x,y) _can_ be specified.
system	Character. Default is MODIS. Alternative is the SRTM tiling system!
zoom	Logical, default TRUE. The interactive mode is only activated if no other extent arguments ("extent","tileH", "tileV") are specified. If zoom==TRUE the first 2 clicks on the map are defining the zoom-in area, and the next 2 clicks the download area. For large areas you can set to FALSE.

Details

extent:
If "list":
	Then LatLon coordinates in the following form:
	list(xmin=mumeric, xmax=mumeric, ymax=mumeric, ymin=mumeric).
If "character":
	the country name of a map object (see package maps), you can use ?search4map to find a map by regular expression.
	Or the file name (plus path) of a raster* or a ESRI Shapefile (shp).
Other:
	If "rasterLayer","rasterStack" or "rasterBrick" (package raster).
	Using a raster* object as "extent", the function determines the "extent", "resolution", and the "projection" from that raster*. This will be used by "runGdal" creating perfectly matching files. If the raster file has not a valid CRS string it assumes LatLon!)
	Using an "extent" (package raster) object, it must be in LatLon, as the extent object has no projection information attached.
	If ESRI shapefile (shp) or maps:::map object, a call to sp:::over is performed to determine MODIS tile containg the "extent", this often considerably reduces the number of required tiles but can lead to NO-DATA areas if in the bounding box of 'extent' not all tiles had to be downloaded!

PS:
If an extent is specified through tileV, tileH arguments, no cropping is performed and the full un-cutted tile(s) (if more than one then also mosaicked) is/are processed!

Value

List

Author(s)

Matteo Mattiuzzi

See Also

raster package: ?extent,?raster,?stack,?brick or ?shapefile

Examples

## Not run: 
# ex 1 ############
# drawing the extent. NOTE: It is not possible to draw a date-line crossing area!
# draw extent with zoom, for smaller extents
getTile()

# ex 2 ############
# "extent" specified with a vector file (map or shp)
japan <- getTile(extent="Japan")
japan
# and here the same "extent" using the bounding box 
getTile(extent=japan$extent)

# ex 3 ############
# with tileH and tileV
getTile(tileH=18:19,tileV=4)

# ex 4 ############
# with extent of class "list"
Austria <- list(ymin=46.12,ymax=49.3,xmin=9.2,xmax=17.47)
getTile(extent=Austria)
getTile(extent=Austria,buffer=10)
getTile(extent=Austria,buffer=c(0,10)) 

# ex 5 ############
# with extent or raster* object from raster package
# rasterObject
rasterObject <- raster(xmn=9.2,xmx=17.47,ymn=46.12,ymx=49.3)
getTile(extent=rasterObject)

# raster extent
ext <- extent(rasterObject)
getTile(extent=ext)

# rasterObject in UTM33N
CRS <- "+proj=utm +zone=33 +ellps=WGS84 +datum=WGS84 +units=m +no_defs"
rasterObject <- projectExtent(rasterObject,CRS)
extent(rasterObject)
projection(rasterObject)
getTile(extent=rasterObject) 

# ex 6 #################
require(mapdata)
# Character name of a map contained in "map("worldHires",extent,plot=FALSE)".
# Use with caution! The following example includes much more areas than the main USA. 
map("worldHires","usa")

# Maybe before using this option run a test map("worldHires",yourCharacterExtent).
# Check awailability of maps with: 
map("worldHires",plot=FALSE)$names
# or 
search4map("Gua")

getTile(extent="usa")
# it is also possible to put an map object. In this specific example the low resolution map is used!
# in such case polygon matching is used see ex 2
getTile(extent=map("usa",plot=FALSE))

# also possible: 
ext <-  map("state", region = c("new york", "new jersey", "penn"))
getTile(extent=ext)

# or:
getTile(extent=c("austria","germany","switzerland"))

# SRTM data
getTile(extent=c("austria","germany","switzerland"),system="SRTM")



## End(Not run)

MODIS documentation built on May 2, 2019, 6:09 p.m.