GPS Data Loggers

This web page reviews two GPS Data Loggers I have tested recently. My goal was to use the recorded GPS tracks to geo-encode the photographs taken with a Nikon D200 camera. I specifically wanted a GPS receiver and logger that could be carried in my camera bag and had sufficient battery life and storage to operate for several days without any manual attention. Many GPS devices have a very short battery life (10-24 hours) and I absolutely did not wish to deal with constant battery changes or charge cycles. I found two such products:

• The Super TrackStick

• The Gisteq PhotoTrackr

I have included a summary and some additional notes concerning Geo Tagging.

Legal disclaimer: the following expresses my personal experiences with and opinions of the referenced products. If you or your attorney disagrees or doesn't like my comments, please read this.

http://www.trackstick.com/super_trackstick.htm

I purchased one here on 9/7/2007 for $198 plus shipping:

http://www.buildyourumpc.com/Super-TrackStick-Designed-for-Google-Earth-p/supertrackstick.htm

It arrived right on schedule on 9/14/2007 via UPS Ground. The device was well packaged with a single sheet of paper; an errata for the PDF documentation that ships with the software.

The Super TrackStick itself appeared to be solid and well built with a plastic and rubber case. It looked as though it would survive any unscheduled drop tests to which it might be subjected. It also appeared to be quite weather-proof; I imagine it would easily survive a few showers but I wouldn't want to expose it to torrential rain or immerse the thing in water.

It shipped with two accessories; a belt clip and a magnetic clip. I set both of those aside. The molded case does have a "hole" through which a nylon cord can be threaded. I attached a spare wrist strap from a small point-and-shoot digital camera. This was perfect for my needs.

The Super TrackStick has a rubberized cap on one end that protects a standard USB connector. It fits well but not perfectly. There is a sliding on/off switch that doesn't have a very positive feel to it although that may attributable to the rubber and weather-proof design.

I installed two AAA batteries and hooked it up to my computer via a USB port. I had already downloaded and installed the TrackStick Manager software before my Super TrackStick arrived. Installation (on Windows 2000) was straightforward and entirely uneventful. The software appeared to be quite comprehensive and polished/professional.

Satellite reception was reasonable but not great. Indoors, it was generally not able to acquire a fix. On a few occasions with the device immediately adjacent to a window it was able to lock on. Outdoors, it would generally acquire a fix provided it was oriented with the antenna-side-up. In the car, it would acquire a fix provided it was placed antenna-side-up, on the dashboard immediately adjacent to the windshield. However, with less than perfect positioning, it was often unable to acquire a fix; for example, when carried in a pocket outdoors. Overall, the reception quality was rather marginal -- not dreadful but certainly not great either.

The TrackStick Manager software supplied has been very well designed. It seemed to be completely robust and I did not experience any unexpected or unreliable operations. It was extremely easy to use and integrates well with other applications. The recorded data may be saved in a number of different formats:

.tsf	TrackStick proprietary format (binary)
.kml	Google Earth format (several options available)
.html	A fairly decent HTML web page with links to Google Maps
.rtf	Rich Text Format
.csv	Comma delimited text
.gpx	GPS Exchange Format

I have one significant concern with the TrackStick data files. The GPS timestamps are written with a resolution of one minute. They are written in hh:mm:ss format but the seconds value was always zero. I consider this a major flaw. The timestamps should have a resolution of one second, or better.

The Super TrackStick has 4MB of flash memory. This appears to be sufficient to store around 16,000 TrackStick records. That's sufficient to log a record every 5 seconds for almost 24 hours. However, the TrackStick has a lots of smarts and does not log new records if the device doesn't move. So, even with 5 second logging and some periods of no movement, the memory capacity will handle considerably more than a day of data. In addition, the TrackStick can be configured to log one record every 15 seconds or 1 minute, 5 minutes, even 15 minutes. Potentially the unit could handle months of data.

I purchased the Super TrackStick (in preference to other cheaper data loggers) largely for the advertised battery saving features. Battery life is a critical issue for me and I had relatively high expectations. The device uses two AAA batteries and the manufacturer's data sheet states that 1 month of usage is typical. The Super TrackStick incorporates a vibration sensor. When the sensor detects approx. 5 minutes without any apparent movement, the device sleeps to conserve power. It wakes up when movement is detected.

Sadly, the battery management features were pretty much a disaster for me. Firstly, battery management isn't enabled until the TrackStick has acquired its first fix. Hence if you turn the device on while indoors, it will try continuously to obtain a fix until the batteries are exhausted (16-24 hours). Once the TrackStick has acquired a fix, battery management kicks in and, if the device is left perfectly motionless for 5 minutes, it will go to sleep. As soon as the device is moved, it wakes up and seeks to acquire a fix. Unfortunately, if it's indoors with no signal, it will continue seeking a fix until the batteries are exhausted (16-24 hours). So, take it indoors and accidently nudge the thing a while later and, the batteries will be exhausted in less than a day. For me, this made the whole battery management feature completely useless.

I contacted TrackStick for help/advice and they told me the unit was not designed for indoor use and it should be powered off when taken indoors. This was unacceptable to me and at this point I returned the unit for credit.

http://www.gisteq.com/phototrackr.html

I purchased one here on 9/17/2007 for $99 shipping:

http://www.semsons.com/qiphfordicag.html

It arrived right on schedule on 9/19/2007 via USPS mail. It was well packaged and came with several accessories including a wall charger, car charger, USB cable, lanyard, software CD, and a minimal instruction card.

The build quality of the device was hugely lower than the Super TrackStick. The plastic case did not look like it would survive much in the way of drop testing. The battery cover had a poor fit and fell off when I slipped the unit into my pocket. And the design of the lanyard attachment is such that, if the battery cover is removed, the lanyard is detached from the unit. This is all a bit academic because the lanyard has a plastic quick-release that broke as soon as I tried to attach it. It was definitely not weather proof.

I installed the cell-phone like battery and charged it up. Satellite reception was excellent and much better than the Super TrackStick. Outdoors, it always acquired a fix quickly, no matter how it was oriented. It worked when placed in my pants pocket. It worked almost anywhere in the car. And, frequently, it worked indoors.

It didn't work when I placed it a steel file cabinet. However, the PhotoTrackr does support an external antenna and I purchased one with the unit (for $12.50). The file cabinet gave me the opportunity to test it. Sure enough, with the PhotoTrackr in the file cabinet and the external antenna on the floor of my office (10 feet from a window) the PhotoTrackr was able to obtain a fix.

Like the Super TrackStick, the PhotoTrackr includes a motion/vibration sensor to aid in battery management. Unlike the TrackStick, it works effectively, indoors or outdoors. After 15 minutes (the time is adjustable within limits) it goes to sleep whether or not it has acquired a fix. On movement/vibration, it wakes up. It works!

Sadly, the PhotoTrackr software is, in my not so humble opinion, dreadful. Some of the issues...

1. Unlike the TrackStick software which basically manages the GPS receiver and logger, PhotoTrackr wants to manage all of your photographs. Worse, it's hopelessly incomplete for that task. And worst of all, it's clearly very buggy and I certainly wouldn't want it updating the EXIF/IPTC data fields in my precious images.
2. It incorporates a pain-in-the-ass activation feature which is broken. I had to "activate" the software more than a dozen times before I could get it running. In looking at the Gisteq support forums, others have reported similar problems.
3. The "Export to Google Earth" function appears to be broken. It could not find the following file name:

   F:\PhotoTrackr\F:\PhotoTrackr\LogFiles\1200...
   

I really, really hate this program. It tries to do everything, and then fails to do anything effectively. It places itself at the center of the universe. It is is clearly designed to be a controlling program and not one that plays nicely with other tools. This and the rather nasty activation feature suggests a certain level of arrogance by the creators, I think.

The PhotoTrackr is a derivative of another product called Xaiox iTracku. Some software produced for that device does appear to work with the PhotoTrackr. At least, it will download and create log files. It is probably inadvisable to use this software for setting up the PhotoTrackr because there's a risk of messing up the firmware. That software is available here.

The interface has been implemented entirely in German. I don't speak, read or write German. Nevertheless, I found the software (in German) more intuitive and easier to use than the PhotoTrackr software (in English). I think that speaks volumes!

I will most likely use the supplied PhotoTrackr software only for configuring the device, uploading new firmware etc. For downloading the GPS coordinates and purging them from memory I will most likely use the iTracku tool since it is so much faster and cleaner.

http://www.carto.net/projects/photoTools/gpsPhoto/

gpsPhoto will write the lat/long/elevation coordinates from the .gps file to the EXIF data in each image file. Since gpsPhoto uses Phil Harvey's most excellent Exiftool library, it supports almost any file type (including Nikon and Canon RAW files).

gpsPhoto is written in Perl and this may not be suitable for all (or even most) users. However, since I am a proficient Perl programmer and the software is distributed in source code format, it is perfect for me. I always have the option of making changes to the program to correct bugs or add additional features that I need. In fact, I have already integrated gpsPhoto with some home grown Perl code for adding additional IPTC tags to my images.

I will mention two other programs that can be used to geo-encode images including Nikon NEF files. I have played with these two programs only very briefly:

• http://www.robogeo.com/home/ is a commercial program.

• http://code.google.com/p/gpicsync/ is apparently free.

© Copyright Malcolm Hoar 2007
malch at malch dot com
September 2007