I've recently had the opportunity to test-drive the AMOD AGL3080 GPS Logger. For the past three weeks I've been within 15 feet of the AGL3080 at all times. It's sat in my pocket, on my car dash, in my backpack and I've even carried it around the house in my hand- Just to get a feel for it.

And... I'm impressed.
My DG-100 has a serious contender for pocket-space in my future photowalks.
Here's why:

./history

AGL3080 Front. 3 status LEDs: memory full, satellite lock, low battery... yummy.

AMOD has recently relaunched the AGL3080. Their first-gen release was sadly flawed and suffered from susceptibility to RF interference, making the GPS module very inaccurate. AMOD seems to be pretty actively chasing down owners of their first-gen device, and offering upgrades, so if you own an old AGL3080, you should get in touch with them! The new version works flawlessly.

./drivers & format

The AGL3080 is a driverless GPS logger, which means it mounts as a USB external drive. If you read my blog post about the DG-100, you know that driver issues with many GPS devices can be a #*$@!'ing nightmare, especially if you're on a Mac!

The AGL3080 saves each GPS track in NMEA format (although oddly enough, it gives each file a .log extension, so make sure GPSbabel doesn't mislabel it as a Geogrid file!)

Convert your file into GPX format to use with GPS Photo Linker or HoudahGeo, or convert it to KML or KMZ to throw into Google Earth.

The device uses the SiRF III chipset, which, personally, is the only chip I trust for good reliability & accuracy- especially in urban environments. (Recently, I've heard good things about the Nemerix chipset used in devices like the iBlue, but it still doesn't have the sensitivity of the SiRFstar III chipset, so no cookie for you.)

This puts the AGL3080 as a front-runner among the small handful of GPS loggers worth considering.

./form & function

AGL3080 Back. 3 AAA batteries for 15 hours of continuous use. No USB-charging, though.

The AGL3080 takes 3 AAA batteries for about 15 hours of use per charge. It's very sleek & solid and it fits perfectly in my hand or in my pocket, however it's not as flat as the DG-100, so it doesn't stay put on the car dash quite as nicely. The front is smooth & glossy and the The battery-compartment door (frequently the first part to break on many of my devices) is rugged and easy to open. It has a built-in carabiener hoop, à la Sony GPS-CS1. (Similar to the Sony, the provided carabiener and strap are shite, replace ASAP.)

As I find myself slowly adapting to life in Japan, the carabiener hoop is begging me for a cute dangling cell-phone toy. Update on that to follow.

The device logs position, altitude, heading, speed, acquired satellites, hdop & vdop every 1 second and saves it to its 128mb of flash memory. It creates a new log file for every time the power is cycled, so it's fairly easy to identify tracks if you're looking for a particular day's data.

Sample GPX output. The AGL3080 logs: lat, lon, elevation, heading, speed, satellites, hdop & vdop @ 1Hz. Impressive. Textmate screenshot using skitch.

Richard Akerman has identified an interesting quirk where the log files are missing the standard filesystem created/modified datestamps, though it doesn't seem to affect the data.

While 1Hz logging may be a tad on the excessive side, it provides very good resolution (although I would recommend using a quick GPSBabel filter at download to strip out excess track points within 5m. You can chop your GPX file size by about 2/3 with no reduction to your precious data.)

The AGL3080 won't recharge your batteries over USB like many other devices. Instead, go buy a good wall-mount battery charger. Your rechargeables will charge faster and stay healthy for much longer. Still, it's a feature that many will find important in chosing their first GPS logger and sadly the AGL3080 doesn't support it.

./bottom line

AGL3080 & DG-100. Both devices use the SiRF III Chipset for near identical results. Shown: Route 38 - Takikawa (滝川) to Ashibetsu (芦別), Hokkaido, Japan on Google Earth

Okay- here's the verdict. The AGL3080 hands down beats the DG-100 for one reason and one reason only. Data.

We geocoders are interested in collecting quality GPS data to tag our photos, videos, blog posts, etc. My DG-100 logs only a small subset of available GPS data. (position, altitude and speed) The AGL3080 logs position, altitude, speed, heading, acquired satellites, hdop and vdop (Dilution of precision... look it up.) USB-charging and logging frequency are one way to evaluate a device, but if it doesn't log every single piece of available GPS information, why bother carrying it around with you?

This, of course, is extremely subjective. Some people don't place as much importance on maximum GPS data; they want the smallest device possible, or USB charging- and that's all fine; there are plenty of other GPS devices on the market that are better suited for those criteria. But for me- it's all about the data.

Oh- and the fact that it will work on my Mac without spending a few dozen hours hacking around with a C script is pretty cool too. =)

You can get your hands on a AMOD AGL3080 through semsons, amazon.com or you can contact AMOD directly.

Review & Photography © Kevin Jaako, 2008. All rights reserved.

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A few months ago, Cathy & I bought a Globalsat DG-100 Data Logger straight from the local distributor in Taiwan. I was pretty thrilled with it until I tried hooking it up to my powerbook and learned that Globalsat only wrote their lousy, buggy software for PC.

An exhaustive web search turned up a few surprise results from friends Boris Mann and Richard Eriksson (neither of whom had luck with the device either) and unfortunately not much else. There was talk of coming support for the DG-100 in GPSBabel, but the "coming soon" tag had been up for months with no results. Update (09/03/08): GPS babel has recently released a new version with DG-100 support!! (skip this hack, and go download the new version!)

Recently I stumbled across a beautiful C script written by Mirko Parthey that had it pretty much figured out. I hacked together a GPX output function and my DG-100 and my Mac are now very good friends!

First, you will need to grab the PL2303 USB to serial driver from sourceforge. Then download (or install from CD) Xcode from Apple.

Once you're done, grab my revised copy of Mirko Parthey's dg100.c which includes several small bug fixes and GPX output mode and you're ready to go. Compile the program with gcc dg100.c -o dg100read and run it from terminal using ./dg100read > myGPSfile.gpx to redirect output to file. To change device functions (read/delete/etc), uncomment the desired lines from the script and recompile.

Its pretty unglamorous, but it's simple, reliable and it works on a mac.

A few things to note:

- Don't fall into the trap of only installing Xcode gcc! you need the header & library files. Install it all!

- The DG-100 mounts on my system as /dev/cu.PL2303-3B1. If this is different for you, cd to /dev/ and find the appropriate device name and stick it in the C script.

- The PL2303 drivers are a little strange. The USB port you have the DG-100 connected to will affect it's device name. "3B1" is the address of my powerbook's right-side USB port. You'll either have to keep using the same USB port, or recompile if you ever need to change ports.

- sometimes port_close() doesn't end the session with the DG-100 properly. If the program stops responding normally, just reboot the DG-100.

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