When your digital camera saves an image, it probably saves it as a JPEG. (If you don't know whether it does or not, it almost certainly uses a JPEG!)
"The JPEG" is the file that you copy to a hard drive to "have a copy of the picture on" your computer. And copy to an external hard drive too, I hope. Computer's hard drives fail.... taking your photos with them. External hard drives fail, too... but not normally the same day your computer's drive fails.
The JPEG not only contains the picture, but it also contains other information. For example, it will record the date and time the picture was taken. Well. The date and time in the camera's internal clock at that moment, anyway. We'll get to geotagging in a moment. First a bit about date/time stamping, which is essential to geotagging.
Speaking of date/times: A tip: Set your camera to "UTC", or "Zulu" time... i.e. the time in London England, in the winter, when they are not on Daylight Savings. (In the summer, when it is 10:00 by UTC, the locals are calling the time 11:00.) If (January 2011) you type "What time is it UTC" into Google, it will tell you the UTC time.
Having set your camera to UTC, don't change it. Leave it always on UTC. You won't have to remember to change it spring and fall, if you live where Daylight Savings is observed. You won't have to change it... twice (going out and coming back) if you travel to a different time zone.
With just a little "getting used to it", you will find that you can cope just fine with your photos being date/timestamped in UTC. I usually photograph my wristwatch after resetting it for any reason... that can help me recall the local offset from UTC when the need arises.
Besides storing the date and time a photo was taken, JPEGs can store where the photo was taken. The location is stored by recording the place's latitude and longitude. Lots of other things are stored as well. If, under Windows XP anyway, you right click on an image and select "properties" on a freshly downloaded (from your camera, to your computer) JPEG, and then go to the "Summary" tab, and click the "Advanced" button, if "Simple" isn't showing, you SHOULD see all the "stuff" that was saved inside the JPEG. This data is called "metadata". It can be lost if you edit the image with the wrong photo editor.
If you put the latitude and longitude of where a photo was taken, various things become possible. You can display them on a Google Map, for instance. Flickr ("YouTube" for still photos) will automatically put them "on the map". Panoramio (similar to Flickr, but Google may use your photos, if you want to help build the Google resource.) Wikimapia is another worthwhile collaborative venture using geotagged photos.
In all three cases, you would of course be able to determine the latitude and longitude for, say, the Taj Mahal, after the fact. I have some nice photos taken on a cruise down the Nile. In some cases, I manually noted where they were taken, using my non-track-recording GPS. If I'd had my geotagging datalogger, I would know where all of those photos taken. "Between Luxor and Cairo" doesn't hack it with the geographical sites!
Want to know the lat/long of a place? There's a neat online tool: Geotagger. It has extra features to help Flickr users, but is a fine general purpose tool, too.
And there are tools (I like the free Exifier, but at that site, the author encourages you to try even newer products. I bet the marvelous Irfan has a plug in for data editing, too, by now) which allow you to alter the data in your JPEGs by hand. But if you think I'm doing much of that, you are wrong! (The data is stored in ExIF fields, hence the name of the software. You may want to know that if you are doing Google searches. There's a Wikipedia article on ExIF data, of course! A complementary system is called IPTC.)
But, finally, we are coming to the reason I started this page!
Not only can "ordinary" GPS units be used to collect latitude and longitude data for "typing in" to photos... automatically, more on this in a moment... but dedicated units, not very expensive (considering what they do!), are available. They aren't "new"... but they are "new" at hobbyist. tourist prices.
In January 2011, I went on a long search (online) looking for "my perfect GPS geotagging data collection device".
In the end, to me, the following were important....
I forgot to "ask for" software... more on this in a moment. Sensitivity and start up times are important distinguishing properties, too... but how would you or I assess them before purchase? A "WAAS capable" device is more sensitive than older, non-WAAS devices, I believe.
You might also want to ask if the logger can be powered from alternate sources, e.g. a car's accessory outlet.
Data Interval: Any GPS logger will note where it is "every so often". A really crude one might do it, say, every 20 seconds. Period. A good one gives you choices.... either every "X" seconds, OR whenever the device has moved more than "Y" meters (or yards)... and you should be able to choose your "X" or "Y". I suppose a fancy one would be able to mix the two criteria. It would, for instance save the device's position at least once a minute, but sooner if the device moved more than 20 meters... but I haven't seen one like this.
Easy operation: Very subjective, and again hard to check before purchase, but what do you have to do to operate the thing? If you have a display, my preference, you will have some sort of buttons + menu system. And we all know how good... or bad... they can be. When you switch any GPS unit on, it has to "acquire some satellites". How do you know if your unit has done this. How do you know it's memory is full? That the battery isn't low?
File formats: As a minimum, you should be able to extract from the logger something like....
2011-01-06T13:16:00Z lat.=50.851681, lon.=-0.713049, Alt.=49.184830 2011-01-06T13:16:02Z lat.=50.851677, lon.=-0.713041, Alt.=44.970963 2011-01-06T13:16:07Z lat.=50.851654, lon.=-0.712926, Alt.=35.144791 2011-01-06T13:16:12Z lat.=50.851521, lon.=-0.712288, Alt.=-10.78790 2011-01-06T13:16:18Z lat.=50.851524, lon.=-0.712471, Alt.=-0.724888
All the labels are beside the point. The fact that the raw data of date, time and location are available is important... unless you want to be tied to the manufacturer's software!
A "g-mouse compatible" unit can be plugged into a laptop via a USB cable. And when that has been done, the laptop has GPS capabilities. With the right software, you can have a display on the screen showing you where you are. As on a dedicated navigation GPS.
Indirect write-data-to-photos: With some geotagging units, you take the memory card from your camera, and plug it into your datalogger at the end of the day. This will be fine when everything goes according to plan. When did that every happen? I want more control over the process. I want to put the photos on the computer, take a "scratch" copy. Then, separately, put the "where/ when" record on the computer, and THEN see about marrying the two. If all goes well, the "scratch" copy becomes my geotagged "main" copy. If things go wrong, I haven't lost my "best" copy of my photos. Whew.
So! That was my "wish list". Because of it, I came down to the Holux M-241, a Sony GPS-CS3KA (much more expensive, and a similar unit which didn't seem to come from such a well established manufacturer.
I went ahead with the Holux, £51, inc p&p from hsuuk.com... "Highest Standard Ultimate UK"!... and have been delighted with my purchase. I hope you'll at least skim down to the end. The best is last!
The first day I had it, I used it without hassle. I put a battery (supplied) in, turned it on, and drove into town. Round trip: 9.3 miles, my GPS logger tells me. Along the way I took a bunch of photos.
It is with deep regret that I have to report that early in 2016 something happened, and the Holux ezTour is no longer able to pull Google maps from the web.
I tried upgrading to the latest version. I tried contacting Holux (no reply)
The device does seem still to connect to the PC over the USB, and if you keep saying "Stop scripts", I THINK you can download data logs from the M-241, save them on the PC. But I don't know how you then use, or even display (as graphics) those files.
So much for Google "doing good".
I would be extremely grateful for news of any work-arounds. The M-241 is an excellent capture device, and the ezTour software was excellent... I might even be able to stand a "fetch file from logger with ezTour/ display in separate app" life. My contact details.
Remember: I hadn't used this device before.
Got home. Transferred the photos to the computer. Transferred the track log from the GPS datalogger to the computer. Married the two.
It all Just Worked. For someone who hadn't used the product before. Were there a few "little things"? Things I'd do differently another time? Of course. But I still ended up with a reasonable result, first time out. (The region at the right hand side where there's a pale yellow blob, with an asterisk in the middle, was redacted with photo manipulation software... that wasn't present in the raw result from ezTour.)
Since writing most of this page, I've owned my Holux for some time. I continue to love it. Always take it with me when, as a licensed pilot, I take small planes up in the air. Of little use for "where am I" during flight, but when I get home, I always review the flight, learn no end of things about my performance as pilot. Sadly, by its nature, the Holux gives me only ground speed, whereas as a pilot I'd also like to know airspeed... but this is no fault of the Holux. Any similar device would be the same.
I also continue to be amazed by the capacity of the device. The device allows you lots of choice in how you set up. You can record a data point every 5 seconds, or at longer intervals. Or, you can record one every 50 feet, or at bigger distances. And you can set it to stop recording when the storage is full, or to over-write the earliest records. ("First in/ first out".) But! The capacity is HUGE... I ran a test once: I made recordings every 5 seconds for TWENTY SEVEN HOURS... and used 18% of the storage!
To see how much storage you have used, connect your Holux up to a PC, go into "Configuration" in ezTour. But! Be sure you have, at least temporarily, elected "Stop Recording When Full" to get a true report of storage used.
And it is easy to "dump" accumulated data to a laptop, using ezTour, and you have just as good access to it later. (If you remember to save "the project", of course!) You can then erase the data in the device, and set out again with the vast capacity all available again.
Battery life is a bigger issue than storage capacity. (A single AA cell runs for... very roughly... a day or so, in moderate use. Obviously, how often you need to replace your battery will depend on your usage pattern. Holux advise against using rechargeable cells. (They run at a slightly lower voltage... an issue for the device, alas.)
One big disappointment: Customer support. My web pages get about 10,000 visits a week, so I get a goodly number of emails asking for support. I know it is tedious. But I was annoyed by the hoops I had to jump through to file an enquiry with Holux, and then doubly annoyed when I got no reply at all. The hoops are there to restrict the frivolous enquiries, I would imagine... so why can't they answer the people who've gone to trouble to ask a question?
I concentrated on the hardware while I was shopping for my geotag data logger. I just assumed that I'd be using one or another of the free utilities I'd heard of to tag the photos with their location data. How card can it be? Compare time in photo with list of times in GPS log, find the best match, write the lat/long into the photo's ExIF. Simples!
The M-241, as is true of many GPS data loggers, doesn't merely appear to the PC as a memory stick/ thumbdrive. So I set about the very simple software install.
When I fired it up, there was a fairly "big" application looking back at me. Okay. I don't need to use all those frills. Clicked on the "Configure" button, and a sensible options panel came up... Bluetooth on/off? (turn it off if you don't need it) Units metric or imperial? Log data by movement or by time? How far/ how long between data points? Great! I wouldn't have to fiddle with the buttons- and- menu control system built into the unit. I could make my settings with a proper keyboard, proper display.
"Read device log" Brilliant! That's what I wanted. Clicked that, fetched the data into the computer.
At which point a maps.Google.com pane opened, with all of the usual functionality present, with my route drawn on it. Wow! And we haven't even started with the photos yet!
Loaded some photos into the project I'd started. This was as simple as you would expect. One little "gotcha": If you say "load this folder of photos", it will... and it will also load any photos in sub-folders within the specified folder. A little strange, but once you know, you just take care over how you store the photos. I haven't researched yet whether the program loads the actual photo, or just a link to where it is at the moment. This is an important and tricky point... but all such programs, and many other (photo album software, for example) have the problem.
Nice touch: I had somehow fluffed the synchronization of my camera's clock with the GPS logger's. (The latter gets its time from the GPS satellites... highly accurate.) But the software let me easily correct the time stored in all the photos
And, hey presto... my map, with the line of my trip on it, now had icons dotted along the line. Click on an icon, and see the photo taken at that point.
Next, I told the computer to write the location data into each photo. Did it without fuss.
Saved my "project". Besides saving it in an ezTour-friendly format, I was also able to export the data from the tracks, so other programs could use it. I could view the "project" (track log + photos) in Google Earth, or so I was told... my computer doesn't have Google Earth on it though. Everything else worked as advertised, though. Why wouldn't this?
As a separate option, I was able to export the project as a .kmz file. This is a Google maps/earth format. Once I had uploaded that file to my web host, I did the following on a separate computer. That "separate computer" did not have Google Earth on it, or I imagine I could have done no end of clever things, but it did have the Google Earth viewer for maps.Google installed.
After calling up maps.Google, I put the URL of the .kmz file into maps.Google's search box... and had no joy. I'd hoped to see something like the amazing result you get if you do the same, but put....
... in the search box. You have to fiddle with the timeline tabs a bit... at least you do on my machine... but you get an animated display of a whale shark's progress through the Indian Ocean. Remember: You need Google Earth, or the Google Earth viewer for maps.Google installed. Why did I get no joy? I don't know. Maybe the viewer can only handle .kml files. I had a .kmz, remember. Maybe it is time for me to explore Google Earth? (Actually... it is time for me to go to bed, but there's more to do here, first.)
I can "export as HTML". This created a bunch of files which, on a separate computer, with an internet connection and Firefox... but no ezTour... displayed the map (scrollable, zoom-able, etc) with a "strip" of photos down the side, and icons on the route trace. Click on an icon, see the photo. I didn't have success posting those files online... yet.
There are buttons for uploading your freshly geotagged photos to Flickr and Locr... not that you need one for Flickr (I don't know about Locr), but it is a convenience, I imagine. (Didn't test it.)
There are tools for editing the track. If you go into a building, the GPS data becomes "a bit funny", so you may want to delete the datapoints for while you were in the building.
Oh! In that vein: The receiver worked fine around my neck while I was in my car. I didn't have to prop it on the dashboard with a clear view of the sky.
We're not done!
Having put the data log into the computer, there's a window showing you a graph of your sped and altitude against either distance or time. It was in kph the first time I looked at it, and I wondered if I could really have been driving that fast on the highway. Changing the units to mph brought relief.
You can have your journey "play" in an animation, at different speeds. Sadly, you have to pick from just 5 choices of speed. Also I haven't yet found a way to enter data about a journey, except by using the datalogger. Happily, Google maps/ Google earth now let you create animations of journeys, from a textfile of "where/ when" data, if you want to enter it that way. (See a discussion at the Google Earth forum, if this interests you.
So! I went to get a GPS data logging device, and came away with one I am very happy with, and a superb piece of software, as well.
N.B.: If you are using the Holux M-241, and you want to harvest data logs from it during, say, a trip: You need a PC with ezTour installed. You won't, as far as I know, be able to harvest tracks from the unit on, say, your hotel's computer and email them home to yourself.
Note also: There is a "start" and "stop" button on the unit. After you turn it on, you must also press "start", to start logging data points. And you need to press "stop" before you switch the unit off. Hey! YOU make a device to record your position at different times without it needing SOME help from its human!
If you don't want to go down the Holux path, a quick read of the Geosetter website suggests that it will do may of the wonderful things that the Holux software does, including the Google Maps integration. It is free, runs on Windows XP or higher (only... sorry), and is commended by the person who gave us the excellent ExIFier years ago. Two "teasers" from the GeoSetter page: "Allows synchronization with track files (NMEA, GPX, PLT, Sony LOG, IGC and others). Localizable user interface: English, German, French, Italian, Swedish, Czech, Spanish, Danish, Dutch, Russian, Japanese, Chinese and Norwegian versions are available so far.
Bottom line: Want to geotag photos? You could do a lot worse than the Holux M-241. If you don't want the display... but I think it is important... you might consider the Holux M-1200E, a newer device. But also, it uses a rechargeable battery. Maybe not important to you.
I have no connection with any company mentioned above. I'm just a satisfied customer. Review initially written in January 2011, when I'd not had the unit long, but at Feb 14 I've had and loved that unit, and never been let down. I've bought two more, just in case my first one ever gets lost. About $40 on eBay, if you are careful. See a page I did about Holux records on a trip in November 2013, for a sample of the Holux's work.
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