Geotagging Photos - Part 1 - Introduction

Why Geotagging?
I own two cameras that I am quite happy with: a Canon 60D and a Fujifilm X100T. Both lack a built-in GPS to geotag photos. While some of the pro models from Nikon, Canon, etc. can have GPS receivers attached (usually these are clipped into the flash mount and attached electrically to the camera via a short cable), these tend to be expensive, can only be used with a particular model and - well - need to be clipped into the flash mount. Since no such accessory is available for the 60D, that point is moot anyway.

The way out of the dilemma is to use an external GPS logger. After some (intense!) research, it turns out that the available models has dwindled over the years. Many of these loggers were primarily designed to be bluetooth GPS receivers for navigation app use ("GPS Mouse") with Logging of tracks and waypoints a "might as well add this since it's just software" sort of deal. And since the market for GPS Mouse devices is dying down with every modern Smartphone having a capable GPS receiver built in, the available models that have relevance for Geotagging photos has decreased to just a few.

There are also apps for Smartphones that use the phone's GPS receiver to put together a track for you. This would seem to be the best solution of all - for one thing, you don't have to take along another device (unless you're one of the weird ones that don't take your smartphone wherever you go) - for another, some of these apps work in close unison with PC or Mac-based geotagging software to partially automate your workflow. The dealbreaker (at least for me) is, unfortunately, the achilles heel of all Smartphones: the battery. Constant GPS usage will drain your battery rapidly, so while you might not have to take along a GPS tracker when you use an app, you would have to take along a power brick to charge your phone halfway through your trip.

Geotagging Workflow
What you need for Geotagging post-trip is one or more datasets of GPS locations (and auxiliary data such as elevation) that have time-of-day information associated with the location information (all loggers do this). By knowing the possible offset of your camera's time and the actual GPS time, you can then us a special geotagging software to add the GPS location data that is related to each photo (associated by the timestamp) to the EXIF data in JPG or Raw camera files, or have an XML sidecar file produced (which has the same name as your image file but contains XML data that photo or archiving software can use to get at the geotag information).

There are several key considerations in choosing a GPS logger for geotagging use:

1) Compatibility
First of all, are you going to geotag on a Windows machine, on a Mac on on Linux? This makes a difference, as some of these devices need special drivers to access the track information and these drivers aren't available for all flavors of IT.
Clearly, a device that connects to any PC, Mac or Linux system via USB as a USB drive is going to be highly universal, as you don't need a driver at all and - assuming the software you will use to Geotag can work with it - you can just drag-and-drop the track file

2) Adjusting the camera time
Somehow, you need to either adjust your camera's clock exactly to GPS time or you'll need some mechanism to figure out the delta, which you can use in most geotagging software to get the right geodata into your photos. Yes, a few seconds difference are not going to be much of an issue for most photo shoots (unless you're shooting out of a driving car or a plane, for example), but getting this right from the start keeps issues from popping up in your workflow.

3) How long will the battery last?
While it is enticing to get a logger with a Li-Ion battery (because, after all this is what we use in all of our equipment), you should be aware that the run time of a logger may not be long enough to cover your entire day trip. If you're on vacation and shooting the sights all day, then you may run into a battery problem. The way out, of course, is to have a second (charged!) battery with you, but not all loggers (think "China") use batteries you can get spares of easily. Some have fixed-mounted batteries that can't be swapped out - in this case, you may have to charge mid-travel using a portable power pack.

4) What format is the track file in?
I'm not a GIS expert, but I understand that there are several formats that geolocation data can be stored in. You need to make sure the software you're using to geotag can read (without errors) the file your logger produces. Need to convert that file first? Add more work and potential for error into your workflow!

5) Can you set waypoints?
While geotagging only requires a set of periodic data sets for position/time/elevation to work properly, the track files generated can actually be used for more: you can use the data to upload tours to Google Maps, for example, or if you're an avid mountain biker you can share cool trips with others. If you want to use your track information for more than geotagging images, you will likely wish to be able to set waypoints to highlight that million dollar view of the canyon or a particular fork in the road.

6) Do you need to need to navigate?
You're out in unknown territory, taking incredible pictures. You've got your GPS tracker with you. You get lost. If your GPS tracker doesn't have a display and a "track back" function, you're going to hate yourself for not spending the extra money. If you're only taking pictures out of a tour bus then that functionality is irrelevant.

In the next blog entries, I'll discuss my viewpoint on choosing a GPS tracker as well as choosing geotagging software for the Mac.


Reformat that SD Card? Think again!

I recently came across a small piece of utility software provided free of charge by the SD Association: the SD Formatter, which is available both for Windows and Mac operating systems. For the Mac, compatibility up to Mountain Lion is listed, I have used it successfully with Mavericks, however.

You may think think that this is some sort of marketing gimmick, but then I read this in a
Wikipedia article (see section “”):

Risks of reformatting
Reformatting an SD card with a different file system, or even with the same one, may make the card slower, or shorten its lifespan. Some cards use wear leveling, in which frequently modified blocks are mapped to different portions of memory at different times, and some wear-leveling algorithms are designed for the access patterns typical of the file allocation table on a FAT12, FAT16 or FAT32 device.[77] In addition, the preformatted file system may use a cluster size that matches the erase region of the physical memory on the card; reformatting may change the cluster size and make writes less efficient.
SD/SDHC/SDXC memory cards have a "Protected Area" on the card for the SD standard's security function; a standard formatter may erase it, causing problems if security is used. The SD Association provides free SD Formatter software to overcome these problems.
[78] The SD Formatter does not format the "Protected Area", and the Association recommends the use of appropriate application software or SD-compatible device that provides SD security function to format the "Protected Area" in the memory card.

How many times have I formatted an SD card? Dunno - quite a number of times. I’ve done this on digital cameras directly (though I believe they don’t actually format the card but rather, just erase the contents, since the process is extremely quick) as well as from my Mac.

This is probably something one should keep in mind, especially with highly optimized Class 10 cards used for HD Video, etc. I would think that erasing the card (often called “formatting” on the camera itself is okay, doing so via the formatting program on a PC or Mac likely will cause issues.