dg-100 gps logger review and comparison

[This information is from 2007.  For the latest information on GPS loggers, please see my other blog, Richard's Tech Reviews.]

Summary: I would recommend the Globalsat DG-100 GPS data logger for Windows users who are fairly comfortable using computers (it's not yet Mac compatible - see below).  The software is a bit more complex to use than Sony's, so it may not be good for novice or inexpert computer users, but it offers many more features.  The Globalsat software does not offer photo geocoding, only location download and mapping; you will need additional software to map your photos.

In Canada, I ordered my DG-100 for US$90 from US store Semsons.com, it included an extra USB charger.

In the United States, you can buy the Globalsat DG-100 GPS data logger from Amazon.com.

UPDATE 2007-11-20: I have reviewed the Qstarz BT-Q1000 GPS logger and Bluetooth GPS with MTK 32 channels/32 hours battery life and other than some software issues of its own, I like it better than the DG-100.  ENDUPDATE

UPDATE 2007-11-23: Work is underway to access the DG-100 from a Mac, see my posting GPS loggers and Macs for more info.  Also note there are Windows software alternatives for downloading from the Globalsat - some are mentioned in the comments.  ENDUPDATE

Comparison Chart:

Globalsat DG-100 Sony GPS-CS1 sensor 20 channel SIRFstar III 12 channel (unknown type) * # of location points stored ** 60000 "360 hours of positions" (about 86400 track points) memory 31MB position interval user configured every 15 seconds battery 2 AA 1 AA battery life ** 20 hours 10 to 14 hours USB built-in external cable (included) recharge over USB? yes no mount as storage device? no yes GPS-mouse mode? yes no Bluetooth no no external antenna jack? yes (MMCX) no multiple logging modes? yes no user-configurable logging modes? yes no software included yes (download and map only, no photo features) yes compatibility Windows only Windows, Mac (Intel OS X 10.4.9) log format GSD (Globalsat format) NMEA

* I assume the Sony is SIRFstar II, but it is not documented anywhere

** Based on various (slightly inconsistent) manufacturer-supplied information.  Globalsat info from manual version 1.1

Above: Sony GPS-CS1 on left, Globalsat DG-100 in centre.

A note about GPS

I have realized that not everyone understands how GPS works and what its limitations are.

In brief, you need a clear sky view, so that the GPS can talk to enough satellites to figure out its position.  Basically the way I think of it is that if you can see a good patch of clear sky, so can your GPS.  This means if you're surrounded by tall buildings, or in a building, or underground, you won't get a GPS fix.

So it's not like a cellphone where you still get a good signal inside a building.

If you have the GPS right in a car window (or a train window) you should be able to get a fix.  I have yet to get a location fix in an airplane.  UPDATE 2007-07-03: Also I got good GPS data sitting in window seats on two different planes.  ENDUPDATE

On the plus side, GPS will work through fabric, I usually have mine in an outside pocket of an MEC shoulder bag, or in a shirt pocket, it would also work in an outer pocket of a backpack, or probably in a purse.

As conditions get worse, e.g. from low-rise houses to skyscrapers, it gets harder for the GPS to get a good signal.

Basically, for a GPS data logger, you should turn it off any time you're going inside a building, or going in the metro etc.  Otherwise it will start logging increasingly incorrect position information, as it tries with escalating difficulty to guess your position.  (On e.g. a Google Earth track display, this usually shows as a big child-like spiky scribble indicating a cloud of incorrect positions many metres wide.)

What's the Point?

I use my GPS data loggers to automatically geocode photos, indicating the position where they were taken for display on Google/Yahoo maps and Google Earth.  (Most typically, via the built-in Flickr maps capability.)  Mostly I am taking photos in cities, which are a fairly challenging environment due to the buildings (more so in US or other skyscraper cities than in the lower six-storey typical European cities).  As extremely detailed satellite images are now available of many cities, it's nice to be within a few metres of the location you actually took the photo, and with a good logger (and the time properly set on your camera) this is possible.

SIRFstar II vs SIRFstar III

I am not an expert, but basically my understanding is S3 is a more senstive chip set.  In my practical experience, S3 gives much better results in challenging city environments than S2.

Details

I already have a Sony GPS-CS1 (see previous review) but I wanted to see if a better product was available.  After reading a good review at GPS Passion, I got the Globasat DG-100.  I am very pleased.  It has many advantages for me:

- it comes with rechargeable batteries that charge automatically over USB

- it has a built-in (albeit very short) USB cable

- it has a better chipset (more accurate positions in challenging city environments)

Above: what comes in the package.

Above: size comparison with Sony GPS data logger, also shows DG-100 with battery cover off.

With the Sony, absent an external battery charger I would have to buy, I have to take many batteries with me (I usually figure on a battery for every two or three days).  This is a hassle and not very enviro-friendly.  Unlike the Sony, the Globalsat charges over USB, so you can plug it into a laptop, or if you're not carrying around a laptop, you can get a USB wall-jack adapter for charging.

I have to strongly warn you that the Globalsat software is extremely non-intuitive.  With the Sony there is some basic software, or you can just grab files off the device mounted as a file system, and then use the files in anything that can read NMEA logs.  With Globalsat, you must use the software even just to access the data logs.  The data logs for some reason are chunked into 95 data point sections, which makes working with them a hassle.  The easiest thing is to merge the files you want (e.g., a day's worth of position logs) and then export them as GPX to use in other applications, such as GPS Visualizer.

In order to do this (assuming you have already installed the necessary drivers from the CD):

1. If you don't have it already, download the latest software from e.g. Globalsat Taiwan support

http://www.globalsat.com.tw/eng/product_detail2_00000090.htm

(you must have the 2007-03-15 version or newer for GPX export to work properly)

2. Connect the DG-100 and power it on

3. Start the "Data Logger PC Utility"

4. TrackRecord->Load Track Points...

5. Select (checkmark) the files you want to Load.  Unless you want every data point from every day available on the data logger, don't select all at this point.

6. Once they are downloaded ("Receive Track points OK") select File->Select All Files

7. Here is the most confusing part: To merge the files, select Map->View Point

(Note: this is explained in the manual, but is tremendously counter-intuitive)

Wait while the data points are consolidated (it may take some time, even on a fast machine).

8. You can now export the merged file to many formats, I use File->Export->GPX...

9. If you want, you can also use the built-in capability to display the points on a Google Map (Map->Show Track Points in Google Map) which is displayed within the Data Logger Utility interface, or use Map->Google Earth to send them to Google Earth (which of course you must have installed first)

User-configurable Logging Modes

There is a switch on the side that lets you choose one of three user-defined logging modes (A, B, C).  The device comes preconfigured for walking, biking, and driving.  The modes determine how often data points are logged, amongst other things.  Of course, you actually have to remember to switch the switch when you change transportation in order to take advantage of this.

NOTE: If you want to log altitude, you will have to set this in Settings->Configuration...
I don't think altitude logging is enabled by default.

Comparison of Globalsat SIRFstar III and Sony GPS-CS1 Tracks

As I indicated, Sony doesn't say what chipset they are using, but as it is 12 channel, it's probably SIRFstar II.  Upgrading this would be the biggest single improvement Sony could make to their device.  As it is, the Sony can be off by several metres.  For example, here are tracks of me on a boat tour on the Seine (yeah I know, rough life).  The Globalsat track in cyan correctly shows the boat tracking in the middle of the river.  The Sony GPS log in orange is so far off that it looks like it is going along the bank of the river, or briefly along a bridge at one point.

More on Track Display and Geocoding

For me, I usually use GPS Visualizer to take GPX format tracks and turn them into Google Earth format displays, it can do more advanced things like make time-based tracks.

For photo geocoding, I use RoboGEO, see a previous posting with some info.

Comments

[Lazzo]

This was a good comparasion, thanx a lot! Have used the Sony GPS CS1 for a while and are thinks it interested to read about alternatives to it. My CS1 have issues in city environments and I think that the concept with "rechargeable batteries that charge automatically over USB" seems like a better solution.

[Chris]

Thank you. You did an excellent job with your review. I just have two questions:
(I'm looking forward to your reply/input)

1. In your Comparison Chart you stated that the Sony GPS unit is Mac compatible. Are you sure about this. I went to the Sony store yesterday with the intention of purchasing the Sony GPS unit. At the store, I noticed the box said on it, for PC only. I called up Tech Support. The person I talked with said "yes, the Sony GPS unit is only for PC's, anyone who is a Mac user will not be able to use this device." It appears that the software that comes with the Sony GPS unit is PC only. And without the software there is no way to get the info from the GPS unit to the photos. This is what I was told.
Are you sure it is Mac compatible? Did you find any supporting documentation that states that it is Mac compatible? Have you tried it with a Mac yourself?

2. I noticed that you wrote this article very recently. I'm not sure if you realize this, but Sony come out with a newer version of the Sony GPS unit that you did your comparison/review on. On Sony's web site it lists two models:

GPS Device
GPS-CS1

GPS Unit Kit
GPS-CS1KA

http://www.sonystyle.com/... ...ame=acc_DIAccessories_gpstracker&Dept=cameras

Both have the exact, price and specs as far as I could tell. I called up Sony Tech Support. The person I spoke with said that both models do appear to be exactly the same according to the specs. But he was able to confirm that the CS1 was the original model and CS1KA was just recently released. He able to find and tell me the dates that each were released. He confessed that he didn't know why both models are up on the site. He didn't know what was different about the new model but we can only assume that the new model is better in some way.

You said in your article that "Sony doesn't say what chipset they are using, but as it is 12 channel, it's probably SIRFstar II. Upgrading this would be the biggest single improvement Sony could make to their device."

I wonder if the new model is now SIRFstar III.

I wonder if the difference in models has anything to do with the Mac Compatibility issue. Although, I don't think this is very likely.

[Richard Akerman]

Chris, in response to your questions:

A1: The Sony GPS is compatible as a file device with Intel Macs running OS X 10.4.9 or later). To use it in this way, you need additional software, e.g. GPS Photo Linker, to match up the files you retrieve from the Sony with your photos.

http://oregonstate.edu/~earlyj/gpsphotolinker/

The software that comes with the Sony is Windows only, as far as I know.

I don't have an Intel Mac, but I rely on the reports from

http://macgpscs1.blogspot.com/

A2: The main difference between the CS1 and the CS1KA is that the CS1 doesn't come with Picture Motion Browser (which adds some mapping capabilities) and the KA does. Also the KA explicitly states it is for any camera, whereas the CS1 was marketed for Sony camera compatibility only (although it worked with any camera anyway).

This is not a big deal (to me anyway) since you can just use GPS Visualizer to convert Sony .log tracks to whatever map display you want.

http://www.gpsvisualizer.com/

If you read my review of the Sony, you will find all of the above information.

http://scilib.typepad.com/science_library_pad/2006/09/my_review_of_th.html

I am fairly certain that the additional Sony software is all that has been added to the KA, if they had changed the chipset, it would be a bigger upgrade and it would be obvious (SIRFstar III chipsets are 20 channel, not 12).

[Marco]

Thanks a lot for this review. I am going to follow your advice and opt for the Globalsat DG-100 + RoboGEO solution, mainly because of its three programmable logging modes and its button used to save a waypoint manually: I would suggest you to add both to its advantages list.

Could you add the accuracy and the operating temperatures of each device to the Comparison Chart?

[Badtz Maru]

Thanks for this review and the updates in the Sony unit review. I've been contemplating geotagging stuff for a while and have started biking so its more relevant now. The Globalsat DG-100 sounds perfect for my needs.

[rbluff]

You may be interested in DGManager.NET

http://sourceforge.net/projects/dgmanager-net/

It's an improvement on the software that comes with the DG-100 and it lets you geocode your photos.

[Marco]

I bought the Globalsat DG-100 and I find it excellent! It would have been nice to have a little display with the time of the day, very useful to set up your camera time settings.

To set or modify the photos date and time EXIF fields I recommend:
Photo Studio
http://www.stuffware.co.uk/photostudio/

For geocoding:
Zoner Photo Studio
http://www.zoner.com/photo-studio
The Xpress is a low priced version of Zoner Photo Studio (only 10 EUR) and offers the full GPS Support function.

[Marco]

I have discovered this other good geotagging software: GPicSync.
It's free and open source.

[david]

Thanks for this review, I wish I had read it before I bought my sony!!!

Do you have to use the globalast software at all? Couldn't you just access the data directly with robogeo and let it figure out how the different chunks of data fit together?

[Richard Akerman]

The DG100 does not mount as a disk like the Sony does, so there is no way for RoboGEO to directly access the data. The data must first be downloaded using the Globalsat application, which knows the specific protocol for communicating with the DG100 to access its files.

[Andrea]

Hello I've ordered i-Blue 747, I suggest you to look for some information about it. It seems a great accessory.

[Ekke Kok]

The merging tip may just have saved the BT-335 from going back to the dealer. As it was the 95 interval chunks made processing the data (we do travel time studies with the data logger) much too time consuming. Using the completely non-intuitive (and not mentioned in the users manual for the GlobalSat BT-335) "Map", "View Points" to merge the files was a life saver! Thanks very much for that great tip!