Tag Archives: core_image

More on iPhoto GPS weirdness

Okay, following on from my last post I geek out a lot here, so here’s a summary: In a test of 1600 images, iPhoto moved the recorded GPS location of a picture an average of 6.17m, and in one case moved the image 11.25m from its correct position.

I created a 40×40 array of points approximately 5m (okay, 5 UTM units apart, precisely) and assigned the locations to JPEG files using ExifTool. These files were imported into iPhoto, then exported. The before and after coordinates were plotted and compared:

  • The green crosses are the original coordinates
  • The red crosses are the coordinates assigned by iPhoto
  • The dashed lines map the before coordinates to the after.

In real life, I realise it’s difficult with most consumer GPS units to resolve points 5m apart. It’s pretty egregious of Apple, however, who appear to take great pains to retain all the camera’s metadata, to mash the stored coordinates so badly.