I am also having a problem with iPhoto placing photos in the wrong place.
For example:
Using EXIF Viewer in Firefox, I get the following GPS information for an image -
# GPS Latitude Reference = N
# GPS Latitude = 39/1,30/1,12087/2500 [degrees, minutes, seconds] ===> 39° 30′ 4.8348″
# GPS Longitude Reference = W
# GPS Longitude = 79/1,25/1,6159/2500 [degrees, minutes, seconds] ===> 79° 25′ 2.4636″
# GPS Altitude = 704/1 m = 704 m
The information as contained in iPhoto is as follows for the same image:
GPS Latitude: 39.501343 degrees N
GPS Longitude: 79.417351 degrees E
GPS Altitude: 704.00 m
Place: Oakland
Garrett
Xinjiang Uygur Zizhiqu
China
Notice that the longitude shows W in EXIF viewer and E in iPhoto. I was in the west.
Another interesting thing is, I was near the city of Oakland in Garrett County Maryland, so part of it is correct.
The picture before this image is correctly place as is the picture immediately after this image.