# Data Filters

GPSBabel supports data filtering. Data filters are invoked from the command line via the '-x' option. It should be noted that data filters are invoked in the internal pipeline at the point that corresponds to their position on the command. This implies that specifying a filter before reading any data ('-x <filter> -f <file>'), despite being legal, will not have any effect. The advantage is that filters can be used intermittently between several variations of input and output functions. It should also be noted that filtering data from different input types can sometimes produce undesirable results due to differences in the native data formats.

Beware that most filters only apply to a certain kind of data. This is usually indicated below by referring to points, tracks or routes in the first sentence which describes each filter or in the table at gpsbabel.org .

&filters;