Location data altered during upload?

[Damon]

Hi,

I've uploaded a number of photos with location data placed in the EXIF by the camera via a linked GPS.

I've found that the location data of several files has been altered during the upload to smugmug process, leading to incorrect locations being displayed via the 'map this' function.

Most of the files are correctly located, just a handful seem to be altered in the process - makes it harder to find the reason since it's not consistent as far as I can see! Actually, the only consistency is that the converted values seem to be numerically less than the real values - meaning they are plotted north and west of the correct location.

The change in location data is mainly to the longitude, I've only found one case where the latitude was incorrect after upload. The change is minor - around 1 minute of longitude or less, and I can always edit the geography...but it shouldn't change at all, so I would prefer to find why it might be happening!

The camera (Nikon D2X) seems to save the data in deg/min/sec format, so it could be that something is being lost in the conversion to the decimal format used in the smugmug system.

Some examples:
http://damonbanks.smugmug.com/gallery/2982968/1/161524150/Medium original lat/long is -35 17' 51" 149 2' 23.25", which converts to -35.2975 149.039791666, and after upload shows up as -35.28475 149.027861202. This is the only example I have where both lat and long have been altered.

http://damonbanks.smugmug.com/gallery/3128496/1/171035660/Medium original lat/long is -35 37' 59.4599999" 150 17' 26.154", which converts to -35.6331833333 150.290598333 and after uploading shows up as -35.6331833333 150.278667869. This gallery has three other examples - they all turn up a mile of so west of the main group of markers on the map when plotted using 'map this'.

Anyone have any ideas why the location data is altered (or seemingly mis-converted) during upload?

Many thanks,
Damon

[ivar]

Hi Damon,

Welcome to Dgrin :wave

The numbers that you gave above, are those the numbers that you have entered (Or have been entered by the software & gps)? Do you have the camera save it directly? Or do you add it later by use of a separate gps&software? If so, what software do you use?

I looked at the second one you linked, and the EXIF actually gives -35° 37' 59.46" 150° 17' 26.15" instead of -35° 37' 59.4599999" 150° 17' 26.154" which makes sense. Rarely do you see anyone use so many digits for seconds.
It could account for some of the difference, but should not account for such a large difference, as 150.278667 is about 150° 16' 43" which comes down to a little more than half a nautical mile of difference on that latitude.

I'll upload your photo to a test account and see what happens. Does this happen to all photos? to some? to most? Please let us know, as it may help us to help you. Thanks!

[ivar]

Some examples:
http://damonbanks.smugmug.com/gallery/2982968/1/161524150/Medium original lat/long is -35 17' 51" 149 2' 23.25", which converts to -35.2975 149.039791666, and after upload shows up as -35.28475 149.027861202. This is the only example I have where both lat and long have been altered.
The latitude embedded in the EXIF for this image is not -35 17' 51", but -35 17' 5.1" which makes the conversion correct.

I'm still looking at what's going on with the longitude.

[Damon]

Hi Ivar, thanks for the welcome and the help!

The location data was saved directly to the file by the camera. No software is involved except for raw conversion with Adobe Camera Raw. I have the original files locally - and the location data is different after upload to smugmug when I compare them.

Sorry for the large number of digits in the examples I provided. I was providing the exact digits displayed in the smugmug edit location function. I'm not worried by any difference in the 15th decimal place - you're right it doesn't make that much difference by then! The camera appears to save location data down to 1 decimal place of 'seconds' when I look at the location data using Nikon View 6.2.5.

I notice that when I use Opanda IExif 2.0 to view the EXIF data, that it doesn't show any decimal place in the 'seconds' field and it shows 10 digits in total for that field.

As you noted, the difference after uploading is a 'minute' or so - which is substantial and not just a rounding error.

The changes to the longitude only happen to some of the photos when uploaded. The majority plot correctly. I've noticed when using the 'map this' function that a handful of the photos are plotted nearly a mile left of where they should be. Of the photos I've uploaded with location data (only 25 or so), I've found 5 with an error in the longitude after upload.

Thanks again for your help.

[Damon]

The latitude embedded in the EXIF for this image is not -35 17' 51", but -35 17' 5.1" which makes the conversion correct.

I'm still looking at what's going on with the longitude.

Woops, you're right. A thousand appologies!

Great, that means that there are no photos I've found with incorrect latitude after uploading, only longitude.

[ivar]

Just a correction/addendum to my previous post; I didn't mean to imply that the decimals on the minutes weren't there, just that most software doesnt read that many decimals. They are definitely there :thumb

http://myskitch.com/ivar/imageinfo-1.jpeg-20070717-114434.jpg

http://myskitch.com/ivar/imageinfo_11-29-20.jpeg-20070717-114941.jpg

I'm not sure what's going on. The strange/difficult thing is that most images seem to behave as they should, and just a few have a mind of their own.

The difference is definitely too big to be a rounding error of some sort. I will bug this internally. I'm not sure how fast this will be fixed though, as it will be a hard one :cry

[Damon]

Thanks again Ivar,

At least you're seeing the same problem I am! That's got to be a huge start!

I'm not sure what's going on. The strange/difficult thing is that most images seem to behave as they should, and just a few have a mind of their own.

The difference is definitely too big to be a rounding error of some sort. I will bug this internally. I'm not sure how fast this will be fixed though, as it will be a hard one :cry

Yeah, the intermittent bugs are the worst. I'll be interested in the cause when it comes to light.

[ivar]

Thanks again Ivar,

At least you're seeing the same problem I am! That's got to be a huge start!



Yeah, the intermittent bugs are the worst. I'll be interested in the cause when it comes to light.so am I/are we :lol3

[Damon]

A few days ago, I manually edited the location data for the files that had the incorrect longitude, but they still plot incorrectly when viewed via 'map this'.

Any ideas why editing the longitude manually still won't allow the photo to plot in the correct position?!

[Damon]

As of today, the photos all plot correctly! :clap

I haven't tried uploading any more yet...