Tag Archive: GPS

i-GotU GT-120 Final Thoughts


Qstarz comparison

As I stated in my last post, the i-GotU GT-120 was a pleasant surprise. The unit functions much better than the GT-100 that I purchased and returned last year. It geotagged images accurately from my little Nikon S50 camera. However, in my last tests I ran into some puzzling problems – not with the GT-120 but with my QStarz BT-1000 and also with my big Nikon D50 DSLR. Where both had worked together accurately for quite awhile now, neither was able to get a geotagged image – the D50 with either GPS tracker, and the BT-1000 with either camera. More tests were needed. The problems appeared to be related to incorrect time-codes, so I started from that basis.

Before I got started with the comparison tests, I did another quick test of the GT-120. On Monday I kept it in my pocket all day. The unit was able to track my location the entire time. Another good sign for the GT-120.

For my first comparison test I set up my Nikon S50 in interval mode, shooting one shot every 30 seconds, and placed it on my dashboard for the drive home from work. I put the GT-120 and the BT-1000 on the dash beside the camera. When I got home I made two sets of the images and downloaded the GPS tracks from both units. The GT-120 geotagged the images with no problem. The BT-1000, however, placed all of the images at the very end of the track.

An examination of the GPS track showed me that the BT-1000 had never reset for Daylight Savings Time. Fortunately, the accompanying software has a time-shift utility. Once I shifted the photos back an hour, it located the images accurately. The image below shows both the GT-120 and the BT-1000 images as located in Google Earth.


Of course, this was still with my little point and shoot Nikon. All of this would be for naught if I couldn’t get it to work with my DSLR. For the second test I double-checked the time on the D50, and sure enough, IT had never been reset for Daylight Savings Time. That’s why the GT-120 couldn’t find any of its images on my earlier test run. The clock was not off by an exact hour, so a when I did a one-hour time shift in my previous test, it was able to geo-locate the image, but not accurately. I set the clock on the D50 to match the S50, and set off for one final test.

As with previous tests I placed the GT-120 and the BT-1000 side-by-side on my dash board and drove to work – the exact same route as the previous test. This time I took random photos out the window with my DSLR. I made sure that I took pictures of intersections and easily recognized landmarks, such as overpasses, so that I could gauge accuracy of both GPS trackers.

With the clock reset on the DSLR, the GT-120 was able to accurately geo-locate the photos without any problems. The BT-1000 was able to locate the images, but only after I had done a one-hour time shift for Daylight Savings Time. There were some discrepancies, though. The BT-1000 did tend to place the images closer to their actual location. The GT-120 had more images that were slightly off. I think this might be due to the update settings on both units. The BT-1000 was taking a location reading every 5 seconds, and the GT-120 was taking one every 6 seconds. That might be enough to throw things off if you want pinpoint accuracy at highway speeds, but not enough to cause problems while walking around with your camera. Fortunately, this setting can be changed on both units.

The image below shows the results of the Nikon D50 tracks from the GT-120 and BT-1000 in Google Earth…


After running all of the tests, I downloaded a new update for the BT-1000 software. The new version does include a check box for Daylight Savings Time. I’ll just have to remember to occasionally check the time on my camera, and to reset it with the time change.

So, which one of these GPS trackers will I use? Not sure for now. The i-GotU is certainly smaller and more convenient. Now that accuracy for both cameras is not an issue, I’ll probably alternate using both trackers. The software for each has similar capabilities, both can output a GPX file, both can output to Google Earth (although the BT-1000 creates smaller KMZ files), and both seem to have similar battery life. The main advantage of the BT-1000 is Bluetooth, and that’s not a feature I use. Right now, it’s a toss up, but I’m glad I’ve got options.

i-GotU Revisited


i-gotU GPS tracker

A little over a year ago I tried out the i-GotU GT-100 GPS tracker from Mobile Action. At the time I was looking for a simple tracker for photo geotagging, and the GT-100’a small size and price ($49 from Amazon) were very appealing. I put the unit through a series of tests, and found it to be completely useless for geotagging, and wrote up two reviews to that effect (Test Driving the i-GotU GPS Tracker, and i-GotU GPS Tracker – Summary Review.) Those two reviews generated lots of hits and comments for this website, both for and against the GT-100.

Subsequently, I was contacted recently by Mobile Action and asked if I would be willing to try out the new GT-120. The unit arrived Saturday and I’ve been putting it through the same tests that I did with the GT-100. So far, I’m impressed, and pleasantly surprised. This unit appears to work much, much better, and geotags images like a charm.


Getting More from Your Auto GPS


I figured it was time for a round-up.  I’ve been talking a lot about doing various things with a GPS, but haven’t gone into much detail.  Chances are that you got a GPS for your car because you feel like you’re directionally challenged, or you just the convenience of plugging in an address and getting directions.  That’s about the extent of what most people do, but there is so much more.

Thought it might be time to talk about automobile GPSs in general, and how they can really benefit a serious rambler like myself.  The one I use is a Garmin Nuvi 205, but most of what I’ll cover here should work with just about any unit.  If you’re into geocaching, you’ll already be familiar with most of these concepts. (more…)

South Carolina Heritage Corridor


While out driving the rural highways of South Carolina you may have come across a road sign with this symbol…

Seeing a road sign like this lets you know that you are on either the South Carolina Discovery Route, or the South Carolina Nature Route, both parts of the South Carolina Heritage Corridor.

On the way back from Charleston Laura and I often get off the interstate and take the country roads home. We have specifically looked for these signs, and once followed the the Nature Route as far as we could.

According to the SC Heritage Corridor website…

The South Carolina National Heritage Corridor extends 240 miles across South Carolina, stretching from the mountains of Oconee County, along the Savannah River, to the port city of Charleston…The South Carolina National Heritage Corridor was established by the U.S. Congress in 1996 as one of a select number of National Heritage Areas…

The Heritage Corridor has an excellent website with links to resources around the state. In particular I like the interactive maps using Google Maps. However, there’s a problem. You can’t really do anything with the maps other than follow the links to resources. What I wanted to do was download the data into a KML file for Google Earth, or, better yet, a GPX file that I could dump into my GPS. I e-mailed the webmaster to see if a KML file was available, but never got a response. So, I took matters into my own hand.

By viewing the page source of the map pages on their website I saw that the data points were hard coded into the webpages (or, more likely, imported from a database via some script). Simply by copying and pasting the page source into a text file I had the data, but it wasn’t yet in a useable format.

I won’t explain the entire process, but I used a combination of MS-Access, various queries, etc., etc., to strip away the excess coding until I had latitude, longitude, and location name. I was able to create a comma-delimited file from this data. Using GPSBabel I was able to convert this into both KML and GPX formats. Problem solved, and now I can (and will) dump all of the Heritage Corridor locations into my GPS so that I can either navigate to them directly, or see them pop on the map as I get close enough.

Even more than that, I’m willing to share. Here are both files, which I uploaded to my wiki site


Geohashing – A Game Based on a Comic



The XKCD comic seen above came out around Christmas of 2006, and formed the basis for a new GPS activity – not necessarily going to a random location and making out, but using random numbers to generate latitude and longitude coordinates.  The process of generating the random coordinates is called Geohashing.  These coordinates serve as a basis for adventure, not unlike throwing a dart on a map and then trying to reach that location.  It’s a lot like Geocaching, but you don’t have to find a little container, and the coordinates change. (more…)

Historical Marker Database


When I’m out on one of my photo explorations there are three books thatI usually have with me – South Carolina: One Day at a Time by Caroline Todd and Sydney Wait, the Delorme Atlas and Gazetteer for South Carolina, and the South Carolina Highway Historical Marker Guide by Judith Andrews.   The latter title has always frustrated me.  While the book itself is a wonderful guide, I’ve always wondered why there isn’t an online version of this available.

The collection of historical markers should be a simple database.  That should lend itself to data that could easily be placed online in a searchable form, perhaps with geodata for various mapping systems.  I checked the “official” state website about the historical marker program, and this is all they had.

This morning I was reading a post by John Lane on his blog Under the Kudzu.  In this post John mentions that he is a contributing editor for the Historical Marker Database, and independently run national project where users contribute information about markers in their state.   So far, it looks like the HMD comes the closest to what I had been searching for.

As mentioned, this is a national project, so there are sections for each county in each state.  There are categories (Education, Entertainment, Forts, Government, etc) as well as search capabilities by keyword or zip code.  There are also sections that highlight specific series, such as “George Washington Slept Here“, Civil War markers, or markers relating to the life of Martin Luther King, Jr.

The individual entries contain a photograph and description of the marker, which is usually the inscription.  Lat/Long coordinates are also provided, along with a link to the location in Google Maps.  There is also a section with links to nearby markers, as well as user-submitted photos of the marker and surrounding area.

Probably the most useful feature of the site is the ability to download GPX files of different data sets to import into your GPS.  If you follow the Google Map link for a location, you can an option to download all of the nearby markers as a GPX file.  More useful, though is the GPX File Download Index, which has each state listed by county.  I plan to download all that I can for South Carolina, North Carolina, Georgia, and Florida (places I’m most likely to be driving) and just keep those on the micro-SD card for my Garmin Nuvi.  That way as I drive past one it will appear on my screen.

As good as the HMD is, there is still one major drawback.  The site relies solely on user-contributed data.  While I won’t dispute the quality of information on the site, it’s not “official”, and has the potential for being incomplete.  In fact, a quick check shows that some states (and some counties within those states) are represented better than others.  For example, a county with as much history as Charleston only has 12 historical markers list.  That just doesn’t seem right.

A better solution would be to have the states maintain their historical markers database and to provide an API or some other method for automatically updating the HMD site as new markers are added.  Users could then contribute ancillary information and photographs.  Even with its limitations, though, HMD is a great resource.

It is worth mentioning that Waymarking.org also has a section for South Carolina Historical Markers.  As with HMD all of these locations are based on user contributions.  I haven’t looked at it closely, but it looks like using HMD in conjunction with the Waymarking series would be a great way to run up your waymarking/geocaching stats.

From Lake Fairfield to Fairfield County


Monticello Store

My last Saturday before heading back to work after Winter Break, and I decided to do some geocaching and photography in Fairfield County.  I had new GPS units to test drive, I had specific locations I wanted to photograph, and I wanted to take some time to swing by my parent’s house.  I had ambitious goals for what I wanted to see and do, perhaps too ambitious.   It turned out to be a day of mixed results – delight and frustration, discovery and missed opportunities. (more…)

Photo Navigation


First a caveat – I try not to review or discuss specific gadgets here at RandomConnections unless I actually have the device in hand and have played with it, either having purchased it for myself, for work, or having swiped it from a friend for a test run. I don’t like to speculate on a device’s capabilities unless I’ve seen them myself. Also, especially this close to Christmas a favorable review might be taken as a “wish list”, and that’s not necessarily the case. So, I tend to stick with what I’ve actually seen.

Today I’m going to break with that policy somewhat. My intent was to discuss a capability rather than a specific device or brand, but it turns out that only one brand has this feature (so far.) I’m talking about photo navigation, the ability to navigate to a geotagged photo via GPS as an inherent capability of the device. (more…)

Memorial Day Caching



Today I went geocaching with John Kaup and his son, Richard. I’ve found that I enjoy geocaching with others more than just heading out on my own. I think that’s why I haven’t been very active lately – it’s been harder to coordinate times with friends who are interested. John and I were actually written up in the Greenville News for geocaching ‘way back in 2002 when the sport was just getting started.

Our trip almost didn’t happen. Apparently this is the weekend for GeoWoodstock VI out in California. The website was getting so many hits that it was hard to get through. I was afraid I wasn’t going to be able to download the caches I needed for this trip. However, I was able to get up early enough to download what I needed and get it uploaded to the GPS units.

I’ve started doing paperless geocaching when I’m on my own. I look up the caches on my Blackberry and upload everything to my Garmin eTrex ahead of time. Since we had a seven year old with us this time, I decided that it would be better to print out the caches we would seek. I selected several parks where there were multiple caches so that we could stay in one place and catch several of them. I decided upon Furman. I had two caches of my own there, and there were three others available on campus. I met John and Richard there, and we were of on our adventure.

Richard was already able to describe to me how a GPS works. I let him use my older Magellan 315. While not as accurate as my Garmin eTrex, the controls are super-simple to use, and he was able to select waypoints and follow with no problem.

While Richard seem to grasp the concepts of geocaching, the more subtle aspects eluded him. He tended to trust the technology blindly, thinking that the GPS’s direction arrow would lead him directly to the cache. We let him run on ahead. In one case we wound up walking a LONG way out of our way to get to the next location. All in all, we found four caches – two of mine and two new ones.


Geocaching is a hot topic at instructional technology conferences right now. As much as I enjoy it myself, I have a hard time figuring out how this might be used in a classroom. About the only way this would work would be to take your class to a location like Furman that has multiple caches. Otherwise it seems like you would have to drag your class all over town to find the caches. I guess you could set up a limited set of caches on a school campus that doesn’t actually go through geocaching.com. Regardless, there were lots of teachable moments with Richard today, and we enjoyed our adventure.

[tags]geocaching, GPS, cache, geocache[/tags]

Creative Uses of GPS


Forget geocaching and geotagging. Some folks are coming up with even more creative ways of using GPS technology. The New York Times ran an article about some of these new uses, which basically involve tracking valuables.

Kathy Besa of Broomall, Pa., has a device about the size of a pocket pager attached to the collar of her 5-year-old beagle, Buddy. If he wanders more than 20 feet from the house, she gets a text message on her phone that says, “Buddy has left the premises.” From there she can track his movements over the Web…

Some parents are throwing a device into their child€™s backpack. An art collector in New York uses one when he transports million-dollar pieces. Every cyclist competing in the Tour de France has one attached to his bike…

A home builder is putting them on expensive appliances to track them if they disappear from construction sites. A drug company is using them after millions of dollars in inventory turned up missing. A mobile phone company is hiding them in some cellphone boxes to catch thieves.

The thing to keep in mind is that these are using specialized GPS trackers. While decreasing cost and increased availability make such applications economically possible, these are still not the same types of GPS units that you would use either for geocaching, auto navigation, or geotagging. The trackers referred to in this article require not only GPS location, but some method for broadcasting that location to a receiving unit. This could either be cell phone technology, radio, or WiFi. Usually there is a subscription fee associated with the device.

These devices do sound like they could save some heartache, but they also smack of intrusion on personal liberties. I’ve already heard of companies that track their employees’ movements via their GPS enabled cell phones. Personally, I’m glad that the GPS technology I use doesn’t have any broadcast capabilities (that I know of.)

[tags]GPS, gps tracking[/tags]

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