I recently uploaded more than 1800 photos to Flickr from Lightroom. Many of those photos have GPS locations in the EXIF, and the Map function in Lightroom shows where those pictures were taken. However, I noticed that the Flickr versions do not have location data. I checked the Publish options and discovered that the "Remove Location Data" had gotten set somehow. I had the problem some time ago and discovered that option and I removed the check in that box at that time. I did not think to check it again because I knew I had not gone to the Options panel to change it. OK, I unchecked the box again and a panel came up asking me if I wanted to republish all 1870 photos, so I said "Yes" and it appears that something was going on but I didn't see any "progress" indications. Whatever was done did not take very long--only a \few minutes--I would have expected the Publication of 1870 photos to take at least 30-45 minutes. When I went to the Flickr albums most still do not have any GPS data. There seem to be about 20 pictures that do have location data, but all of it is erroneous. What do I do to get my GPS data onto my Flickr photos?
My photos are published to Flickr with the GPS locations intact ... I use Jeffrey Friedl's Lightroom Publisher plug-in, maybe you should give it a try.
The reason your update took only a few minutes was because (in theory) it wasn't uploading the photos again, it was only changing the metadata (but apparently the metadata didn't change). Have you gone back to Flickr (for example) an hour after you did this upload to see if the GPS location is present now, sometimes it takes a minute (or a few minutes) for Flickr to show the updated metadata.
Yes, I have been back several times and there still are only the very few (some erroneous) locations shown. So I tried republishing just one of the Albums in the Collection, and the GPS data did get carried over. So the operation that was supposed to republish all 1870 photos apparently doesn't actually do that. I will go through and manually republish all the Albums one at a time (they are all marked to be republished--at least the function did that).