Last month, I wrote about my findings on the experience in using the Beta of Windows Live Photo Gallery to geotag my photos. I wasn’t too impressed with the experience.

This week, a second beta of WLPG was released by Microsoft so I’ve been revisiting the experience of geotagging.

And today, it’s been borne in upon me just what a disaster geotagging in WLPG has proved to be.

You see, I made an assumption. That was that WLPG would not alter any metadata in a photo without my explicit permission and knowledge. Wrong…

I was naive enough to think that WLPG would only write out GPS coordinates to the Exif metadata in a photo when I explicitly added a Geotag using WLPG. Wrong…

I realised that WLPG was reading in IPTC Core Location metadata from my photos and using that to create a geotag in WLPG’s internal database. I also realised that it was copying the metadata into the “Location Created” section of the newly specified IPTC Extension metadata. Since these are a set of text fields that reflect what already existed in the original IPTC Core Location fields, that didn’t bother me unduly.

What I hadn’t also appreciated is that WLPG not only constructs a geotag in its internal database and creates Location Created metadata in the IPTC Extension section, but that it then proceeds to write out a set of GPS coordinates into the photo’s Exif metadata of where it thinks that the photo was taken.

This is an unmitigated disaster!

As I said last month, WLPG makes false assumptions about what the GPS coordinates are. If it doesn’t recognise the contents of the Sublocation field, it uses a GPS position derived from the contents of the City field. If it doesn’t recognise the contents of the City field, it uses a GPS position derived from the contents of the State field, and if it doesn’t recognise the contents of the State field, it uses a GPS position derived from the Country field.

I have a collection of over 40,000 photos. The majority of these have IPTC Core Location metadata that I have catalogued over time. Only a very small percentage of these had GPS coordinates that I had carefully added myself.

Now, WLPG has gone through my collection reading the Location metadata and has written out GPS coordinates to all of the photos containing Location metadata. And, of course, in a lot of cases, it doesn’t recognise the terms I’ve used for a particular location field, so it’s plucked a GPS value out that bears no relation to where the photo was taken.

Worse still, I now have lost the needles of those photos which have accurate GPS positions in a haystack of huge proportions, which consists of photos with false GPS positions.

Aargghh!

Update 23 August 2010

1. I’ve now looked at a backup of my photo collection taken on the 1st June 2010 (i.e. before the WLPG beta was installed). No photos had false GPS values inserted in the Exif at that time. Therefore I conclude that WLPG is the culprit.
2. Contrary to what I first thought, not all photos with IPTC Location metadata get GPS values inserted into them by WLPG – there may be a pattern, but it’s not obvious to me why some files are hit, but not others.
3. However, even though all files are not affected, I have still found over 7,000 photos with GPS values, and of these, only 2,359 of these photos have genuine GPS values that I have explicitly inserted. The rest have GPS values inserted by WLPG itself and which are also inaccurate (false).
4. Some false values come from WLPG ignoring a sublocation, and inserting a central GPS value for the City.
5. Some false values come from WLPG misinterpreting a sublocation and inserting a completely wrong GPS value for another location altogether; e.g. Sublocation: Voortman Bos, City: Heelweg gets interpreted as Voortmanweg in Deventer, 37 kilometres away…
6. Some false values make no sense whatever; e.g. some photos I have of St. Pancras station in London have a GPS value assigned to them of Cuxham, a very small village in Oxfordshire…

All together now: Aaaarrrggghhh!!!

Update 8 September 2010

I posted about this issue on the WLPG Help Forum. Now, Analy Otero, who works in the WLPG team, has posted a response  to confirm that WLPG does indeed write out what it thinks are correct GPS coordinates to image files based on the content of the IPTC Location fields. As she says:

“The behavior you’re experiencing is the design of the feature and we’re working to improve both reliability of the process (to ensure all photos get proper geotags) and to improve the accuracy of the places.”

Unfortunately, I don’t believe that Microsoft can ever sufficiently improve both the reliability of the process and improve the accuracy of the places to the extent where I can trust that accurate GPS information will be included in my images. My experience thus far has been an eye-opener of just how bad it currently is. I see that in the current release notes, Microsoft themselves say:

“Landmarks (such as the Eiffel Tower) are not supported in the current implementation of geotagging”.

The problem is that the textual IPTC sub-location field, in particular, will always be down to what the user decides, e.g. “the stern of HMS Ark Royal in dry dock”. I’d like to see Microsoft be able to give an accurate GPS for that. Of course, they can’t, and so the chances that rubbish GPS coordinates will be introduced by WLPG into an image remain very high.

A further twist is that, apparently, once WLPG has introduced a GPS value (false or accurate) into a file, it can’t ever be subsequently changed by WLPG. Elsewhere in the release notes it states:

If a photo or video contains no GPS data, coordinates will be added when the item is geotagged. However, updating or deleting a geotag string won’t modify the GPS coordinates. Any additional updates to the geotag field don’t change the original coordinates written to the file. (my emphasis)

It seems to me that the way to cut this Gordian knot is for Microsoft to give us a proper mapping interface in WLPG itself (such as Picasa, IDimager, or Geosetter do) so that we can check locations prior to allowing GPS coordinates being written, and to use the map to modify or delete GPS coordinates. That is, writing of GPS coordinates is under the explicit control of the user, instead of something that WLPG does by itself in the background as a write-only operation.

The current implementation of WLPG writing out what it thinks the GPS coordinates should be is dreadful and appalling. I simply cannot afford to have WLPG installed on my PCs as it is. It has already introduced garbage information into thousands of my images.

Update 30 September 2010: Well, the final version of WLPG 2011 is now released, and as far as I can see it is still screwing up my GPS metadata.

I’ve just found some photos taken this month in the Netherlands which now have GPS info for Wimereux in France inserted into them by the final release of WLPG.

I am definitely not impressed.

Update 2 December 2010

There’s an update to WLPG 2011 that addresses the geotagging issue. See here for more information.