Remove unreliable points with high hdop or vdop (discard)

This filter is used to "fix" unreliable GPS data by discarding points with HDOP and/or VDOP above a specified limit. HDOP and VDOP are measures of the best possible horizontal or vertical precision for a given configuration of GPS satellites.

Example 4.14. Using the discard filter

gpsbabel -i gpx -f in.gpx -x discard,hdop=10,vdop=20,hdopandvdop -o gpx -F out.gpx

Contributed by Tobias Minich.

hdop option

Suppress waypoints with higher hdop.

This option specifies the maximum allowable Horizontal Dilution of Precision (HDOP). By default, any point with an HDOP in excess of this value will be discarded regardless of its VDOP, but see hdopandvdop.

vdop option

Suppress waypoints with higher vdop.

This option specifies the maximum allowable Vertical Dilution of Precision (VDOP). By default, any point with an VDOP in excess of this value will be discarded regardless of its HDOP, but see hdopandvdop.

hdopandvdop option

Link hdop and vdop supression with AND.

If this option is used, only points that exceed both the maximum allowable HDOP and the maximum allowable VDOP will be discarded. This option requires that both the hdop and vdop options be specified.