Blanking Options

By default, CDT set a buffer outside the polygons used to mask the grid about 4 times of the resolution of the grid data. You can control the width of the buffer by using the function blanking.options.

On R console you can check the blanking options with

blanking.options()

## $bufferOption
## [1] "user"
## 
## $bufferWidth
## [1] 0

The 2 arguments of this function are:

• bufferOption: a character, options are "default" or "user"

  • "default": a buffer of 4 times of the spatial resolution of the gridded data is used
  • "user": the width of the buffer will be defined by the user in bufferWidth

• bufferWidth: a numeric value indicating the width of the buffer outside the polygons in decimal degree

If you want to mask the grid outside of the boundaries, and exactly at the edge of the polygons, you can use the command below before starting the blanking

blanking.options(bufferOption = "user", bufferWidth = 0)