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Order by. The output will be ordered according to the 'order by' directive.
Example: "step:i asc, centre desc" (step numeric ascending and centre descending)
Default sort mode is 'asc'.
-l Latitudelatitude,Longitudelongitude[,MODE,file]
Value close to the point of a Latitudelatitude/Longitudelongitude.
Allowed values for MODE are:
4 (4 values in the nearest points are printed) Default
1 (the value at the nearest point is printed)
file (file is used as mask. The closer point with mask value>=0.5 is printed)
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