Features from optional dependencies

cggtts implicit feature

Enables cggtts

cggtts:

CGGTTS data parsing and synthesis

csv implicit feature

Enables csv

csv:

Fast CSV parsing with support for serde

Affects fops::csv

gpx implicit feature

Enables gpx

gpx:

Rust read/write support for GPS Exchange Format (GPX)

kml implicit feature

Enables kml

kml:

KML support for Rust