I want to add GPS location to RAW photos (from my EOS7D) using location data from my iPhone 5. Aperture doesn't save the data I added unless I export the RAW files as JPEGs.
Most of the OSX GUI applications for manipulating exif information rely on Phil Harvey's exiftool, an open source perl library and cross-platform command-line tool for manipulating EXIF information. HoudahGPS, Geotagger, and GPSPhotoLinker all rely on exiftool to write EXIF tags. And since exiftool can write to Canon RAW files, these apps are likely to be able to do the same.
You can, of course, also geotag photos from a log file using exiftool directly on the command line:
exiftool -geotag=<trackfile> <image_dir>
where trackfile is your track log (exif tool recognizes several formats including NMEA and GPX), and image_dir is the folder/directory that contains your RAW files. The timestamps in the log file are synchronized to the timestamps in the EXIF.
I have had quite good success with houdahGeo, in particular with Aperture. For this you open the photos you want to geotag from houdahGeo (you can open photos already in your Aperture Library) select them and then geotag them using either a map or a GPX file. Then you can reverse geocode and write the data back to the original Raw files. HoudahGeo then informs Aperture about the metadata change.
Makes a nice geotagging workflow