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fieldset Anchor mask mask mask ( fieldset,list, [string] )
For each field of the input fieldset, this function creates a field containing grid point values of 0 or 1 according to whether they are outside or inside a defined geographical area.
The list parameter must contain exactly four numbers representing a geographical area. These numbers should be in the order north, west, south and east (negative values for western and southern coordinates).
If "missing" is specified as the third argument it will change the behaviour so that points outside the area will become missing values and points inside the area retain their original value. This option is new in Metview version 5.13.0.
Non-rectangular masks, and even convex masks can be created by using the operators and , or and not . To create the following mask :
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