This filter removes points based on their proximity to each other. A point is removed if it is within the specified distance of a point that has come before.
Example 4.13. Using the position filter to suppress close points
The following command removes multiple points that are within one foot of each other, leaving just one.
gpsbabel -i geo -f 1.loc -f 2.loc -x position,distance=1f -o mapsend -F 3.wpt
Maximum positional distance.
This option specifies the minimum allowable distance between two points. If two points are closer than this distance, only one of them is kept.
Distances may be expressed in feet (30f) or meters (10m). If no unit is specified, the distance is assumed to be in feet.