Trim a landsat Image to a Geographical Region

Trim a landsat image to a latitude-longitude box. This is only an approximate operation, because landsat images are provided in x-y coordinates, not longitude-latitude coordinates.

Usage

landsatTrim(x, ll, ur, box, debug = getOption("oceDebug"))

Arguments

x

a landsat object.

ll

A list containing longitude and latitude, for the lower-left corner of the portion of the image to retain, or a vector with first element longitude and second element latitude. If provided, then ur must also be provided, but box cannot.

ur

A list containing longitude and latitude, for the upper-right corner of the portion of the image to retain, or a vector with first element longitude and second element latitude. If provided, then ll must also be provided, but box cannot.

box

A list containing x and y (each of length 2), corresponding to the values for ll and ur, such as would be produced by a call to locator(2). If provided, neither ll nor ur may be provided.

debug

A flag that turns on debugging. Set to 1 to get a moderate amount of debugging information, or a higher value for more debugging.

Value

A landsat object, with data having been trimmed as specified.

Details

As of June 25, 2015, the matrices storing the image data are trimmed to indices determined by linear interpolation based on the location of the ll and ur corners within the lon-lat corners specified in the image data. (A previous version trimmed in UTM space, and in fact this may be done in future also, if a problem in lonlat/utm conversion is resolved.) An error results if there is no intersection between the trimming box and the image box.

See also

The documentation for the landsat class explains the structure of landsat objects, and also outlines the other functions dealing with them.

Other things related to landsat data: [[,landsat-method, [[<-,landsat-method, landsat, landsat-class, landsatAdd(), plot,landsat-method, read.landsat(), summary,landsat-method

Author

Dan Kelley and Clark Richards