Tuesday, April 29th 2014
Map of our trip to Chichester (part)
The live map can be expanded
See this Google map for comparison
As you may know from reading my blog, when I am out and about taking photos, I usually have my geotagger switched on. This useful little device uses satellite data to track my position and record where I am at a precise instant. Later, the log is used to map the position of the photos taken during the outing. This is so useful and I have so come to rely on it that if it failed to work, I would feel quite lost (almost literally!).
The geotagger derives its positions and the timings of those positions from the satellites and in order to correctly locate the photos afterwards, it is essential that the camera’s clock be set accurately. If the clock is wrong, then the photos will be misplaced on the map. For example, if the camera’s clock is five minutes slow, the every photo will appear on the map at the place where I was five minutes after taking it, not at the photo’s true position.
For this reason, after returning home with the new camera and familiarizing myself with the more obvious controls, the first thing I did was to set the clock. For this I take the time from a radio-controlled clock to be sure the setting is as correct as possible. I checked several times that the camera clock was showing the right time1. A point that will become important later is that it was now early afternoon.
On Saturday, we went to Chichester and Arundel, as recounted in Visiting Cissa’s town. When we reached home again, I uploaded the photos to the computer and sat watching the copying process. I suddenly realized that the times on the photo files were wrong! So wrong in fact, that the photos taken in the morning were dated to the day before. This meant that my geotagger record was useless and that I could not map my photos. What had gone wrong?
I checked the time on the camera and it was correct. Why then was the camera putting the wrong date and time on the photos – was it faulty?
It was Tigger who immediately realized what had gone wrong: I had set the clock in the afternoon, not taking into account that the camera uses a 24-hour clock. I should have set it to 15:00 not to 3:00! It was running 12 hours slow.
I now knew why things had gone wrong and this was a relief but I was still left with photos that could not be mapped. Again, it was Tigger who came up with the solution. She had seen, as I had not, despite my almost daily use of the application, that the photo viewer/editor FastStone has a function to change the date and time on photos. Would this save the day?
To find the function, you go to Tools on the menu bar and select Change Timestamp. In the window that opens there is a drop-down selector allowing you to choose whether to alter the file date or the timestamp in the photo’s EXIF data. Below are further setting for, among other things, the amount of change. Having chosen to alter the EXIF timestamp, I set it to add 12 hours. Making sure that I had selected the photos I needed to change, I clicked the Apply button.
FastStone ran the task but had this worked? A glance at the timestamps on some of the photos suggested that it had. Of course, I didn’t know exactly when I had taken each photo, but the timings looked plausible. None had yesterday’s date at least!
I ran the geotagger software to map the positions of the photos. Yes! Every photo appeared on the map in its correct location. Tigger (and FastStone) had saved the day!
It was a silly mistake to make but an easy one to make. Without the geotagger map, I would still have known, at least roughly, where my photos were taken, but having the map makes things a lot easier and is reassuring. This has been one lesson that I will not soon forget!
1I always set the camera’s clock to Greenwich Mean Time and do not alter it when the clocks change. This avoids the necessity of changing the time offset in the mapping programme twice a year, let alone altering both the camera clock and the software when I go abroad.