Thursday, August 30, 2007

MetaData Madness

So, I just got back from a 6 week holiday (fantastic, I'll write about it soon) with 5000 photos and a bunch of GPS tracks, so what happens now?

I use Aperture on my home iMac/24 for most photo management, but it does not 'fit' on my MacBook, so while on this trip with camera and laptop, I though I'd use Image Capture and iPhoto 6 to manage the photos.

Every couple of days, I'd plug in the camera, get Image Capture to just copy files to a folder, with no processing. Next import them in to iPhoto (with the preference to NOT copy to iPhoto's folder) so it is easier to begin viewing, selecting and showing the photos. Next I'd plug in the GPS and copy off the latest tracks using gpsbabel+.

Back home I then went through the whole lot in iPhoto, deleting from the Film Rolls the photos I'd never want (about 50%). I quickly realised that deleting a photo from a roll in iPhoto and emptying iPhoto's Trash did not result in the original being deleted, so I'd have to use iPhoto to export my selection. This was when I realised that I had tweaked a few photos in iPhoto, and after export, they had lost their colour profile and a bunch of exif tags (naughty naughty, even revert did not restore the missing data!!). I would need another way of extracting my complex selection from iPhoto, to import into Aperture.

I had a look in my iPhoto Library Originals, the Rolls were being kept as folders of aliases to the originals, so it was a simple matter of selecting the aliases (iPhoto had been deleting aliases of deleted photos), right-clicking to choose Show Original, resulting in a new Finder window with the originals selected, which can now be labelled for later extraction.

The next step was geotagging the photos from the GPS tracks. They were incomplete (see here) so I did not want to use a completely automated technique (like this). Instead I decided to buy a license for HoudahGeo. One by one, I imported the Rolls, then imported the GPX files that covered that time period. Usually about 50% of the images needed geotagging by hand. This was often because the photos were taken at anchor with the GPS turned off, so it was just a question of selecting multiple images and then choosing a map location for them all in one go. The final step was to reverse-geocode the images ...... a nice little trick in HoudahGeo, it looks up the location in a geocode database online, and fills in the Country and City EXIF tags (great for Smart Folders in Aperture!!).

Now I am finally ready to import the images into Aperture. (One big nuisance with Aperture is the inability to write Latitude and Longitude into images. It has to be done before import.)

I decided that I would retain the grouping by Roll. I made a folder in Aperture for "Trips/Caribbean/Projects" and imported each roll as a project. Next I made Smart Folders for each country in "Trips/Caribbean" then moved those to "Trips/Caribbean/Locations". (Make them first, then move them, or they will not work).

Now I can start making Albums for different purposes, images to give to friends, images to make a book for the boat to say 'thanks', images for Flickr etc.

MetaData Madness, maybe, but I am convinced that looking after the metadata will pay dividends in the future.

Things to remember :

GPX files are always marked up in the UTC +0 timezone, even if you change the display timezone on the GPS (so I do not change mine).

If you move across timezones and you change the timezone of your camera, always remember to take a photo of the current (UTC +0) time on the GPS, so you know the offset to enter when you use automated geotagging tools.

The Finder, Spotlight etc. automatically convert image creation times to your local timezone set on your Mac, so if you want to use Smart Folders to select complete days of photos you will get an offset unless you switch your Mac to the timezone the camera was in (and restart the Finder).

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