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The building of a Personal Learning Environment is also and much about the need to classify the abundant digital data gathered both for future retrieval and present sharing. Categorization of experience in context and as most anything revolves around two axial dimensions: Time and Space. GPS provides the means to passively capture and store both with maximum precision. For that purpose we putted the geottaging abilities of the new Sony HX5A camera to the test and the results are amazingly good (see bellow).

As far as photography is concerned with the plethora of mapping tools around these days, geottaging became a common sense feature which any instructed soul will want to insure. The tools to do so are nevertheless skimpy; mostly because the persistent separation between the device acquiring the signal (typically a data logger) and the camera taking the picture; the desktop software bridging the gap by grabbing the GPS data and trough the association of “Time” adding a posteriori to the EXIF of photos the geographical coordinates (latitude and longitude).

Geottaging: integration is better than combination. Let the camera do the work.

 The previous method has a number of caveats nevertheless:

1. it takes a degree of meticulousity and a certain systematisation of the process, data loggers can only store a given amount of data and if you let pictures accumulate in your camera for weeks before tagging them (say if you are on a couple of weeks holiday abroad and do not take your computer with you) they will likely surpass the logger memory;
2. a chance exists for slight mismatches since the accuracy of the process relies on the close synchronization of your camera´s internal clock with the GPS signal (itself extremely precise) ;
3. the data logger needs to be carried around separately and constitutes an extra source of concern (you have to provide for it´s energetic needs, insure it is charged, insure it is ON etc)
4. the entire thing takes extra time which could obviously be saved if the camera itself was to do the geottaging.

Opening a world of possibilities both immediately (better than search a picture of a  place by guessing it´s “name” or the likely semantics used by those posting it to the WWW, hard enough to figure in a specific language and much more on many different ones - as can easily happen while trying to benefit from the results of individual touristic entreprises worldwide - is to feed the search engine with info allowing to grab anything taken on a specific neighbourhood under the universal language of geographical coordinates, standardized in WGS84. On the long run,also, as far as your private archives are concerned,  you will benefit from geottaing while browsing your photo albums and feeling the need of recalling the exact place where a picture you had forgetten about was taken.

Camera manufactures looking the other way

Still, camera manufacturers insist in not understanding the critical need of geotagging and while mainstream DSRL manufactures such as Nikon started providing for an external GPS entry (either working with the brand's hardwired unit or with an old fashioned serial input, thought to be used in the old pre-bluetooth days where Garmin and Magellan units dominated the market) others like Canon which apart from a top end model simply skip the technology altogether and at best allow you the chance to plug a GPS to your camera at the cost of stockpiling several add-ons, impractical to use in already bulky models and extremely costly.

An absurd limitation which actually deterred me from the otherwise impeccable and more capable EOS550D and has recently trough me in a path – that of cameras with GPS onboard – where currently three models alone are to be found (I understand iPhones and some smarthphone geotag photos, but their cameras seems far from impressive to me): the Sony HX5V; Panasonic TZ10 and the about to be available Samsung WB650. These are models which apart from the GPS distinguish themselves by the large zoom lenses (10x; 12x and 15x respectively).

As far as geolocation abilities are concerned the Sony offers an exclusive bonus to the GPS: an electronic compass which adds to the EXIF the “Magnetic Declination”; that is, the direction/cardinal point the camera was pointing when the photo was shot . Which I find extremely useful, allowing to mimic the “streel level” view of Google.  HX5V also adds the “altitude” of the location, which may be of questionable utility but is nevertheless a more “complete” implementation of GPS in strict terms than the one offered by Panasonic.

In turn, Panasonic has thrown into the camera a database of half a million waypoints worldwide meaning in practice the camera is able to recognize a great deal of landmarks, serving you as a “guide” while taking a shot in a place where you have never been before by showing the label with the name of the interest point on screen. A feature which in “mobile learning” terms is certainly a plus.

The customary “privacy” nonsense

Coupling a GPS with a camera raises a number of concerns and technical practicalities. In fact, while googling for discussions about the need for GPS in cameras, the main concern seems mostly a matter of retrograde taught to me and it is pretty recurrent every time a NTI appears: Privacy. It is said that once pictures get the location they were taken on embedded issues may arise from the fact of "strangers getting to know where you live and somehow 'coming after you' with an undisclosed bad intent". This is of course is valid for most anything made public on the WWW and makes little sense since:

1. You can always turn geottaging off;
2. Even if you kept geottaging on while taking a photo you can always erase that piece of info later;
3. The vast majority of photos placed on the WWW are not “private in your own home” but of places seen during some sight seeing trip or vacation;
4. Most private photos (in family events et cetera) are taken indoors where there is no GPS signal anyway (even if you accumulate the fact of forgetting to turn geottaging off with forgetting to verify if the info was there and or delete it while publishing the pictures )

Speed & signal availability: will it lag the spontaneous shot?

 On the technical side, those familiar with GPS for a long time will wonder: how fast is signal acquisitation? Will I need to wait 50 sec.s before I can take a picture?

Well, a number of things must be taken into account: 

1. Like smartphones, Sony HX5V can use A-GPS (Assisted-GPS) to make signal acquisition faster by downloading an updated set of elements pertaining the status of the satellite constellation from the Internet. Of course this is easy for a network enabled UMTS phone but only possible on the camera provided it is connected to a computer with the supplied USB cable and the PMB software software provided by Sony is installed on the PC. This a strong limitation which will make sense only if you think of docking the camera every morning before going out.
2. You are not dependent of the GPS signal to take the photo; you can do it without it;
3. The camera recalls ephemerides gathered the last time it was turned on, so usually if you are taking photos within a few minutes from each other, only the first will take more time to get a so called "cold fix"; the following should be considerably faster.

HX5V GPS Performance taken to a test

As for the effective performance (signal acquisition speed and accuracy) we have taken our HX5 on a quick test drive. The benchmark used was a geodesic survey point with known precise coordinates and located in almost ideal signal acquisition conditions with a clear horizon all around.

The results are pretty impressive: it took the camera 40 seconds to acquire a cold first fix (the first time it was turn on that day) and hence forth, with fresh ephemerides stored no longer than 3-4 seconds every time it was turn on. GPS actually ads nihil lag to the time the camera normally takes to be ready to take a shot.

Not only it is fast it was extremely precise as well with a negligible different of a few centimetres to officially know values.

Compare the official data with the values recorded in the EXIF by the camera in the following illustrations:

Above: The readings from the camera as stored in the EXIF header of the Jpeg.
Bellow: The actual coordinates of the place.

 Above: The location coordinates (red arrow) grabbed by the camera imposed on a map with the geodesic marker identified as a brown triangle (right "on spot").
Bellow: The set in place. You will notice by the compass we took the photo facing North (roughly 360/0º; the camera recorded 348,5º which is OK since our alignment was likely not perfect). We also took an old fashioned bluetooth GPS (Globalsat 338) along which achieved similar results with a 0.7 DOP and 12 satellites tracked.

 Further bellow you will find a couple of screen shots demonstrating the experience of browsing a geottaged Photo Gallery and of the interface of software provided for configuring A-GPS. Click to see in full size.

Myth debunked: GPS not a Power Hog (10% battery consumption increase)

Since the above post I have found an interesting blog where a user has been subjecting an HX5V to all sorts of interesting tests. One of which a "GPS battery drain test". Taking the results in good faith, the conclusion seems to be that GPS use decreases battery life by about 9,8% (with camera on bright mode an no power saving it took 3 hours and 3 minutes for the battery to drain; while in similar circumstances but with GPS on it lasted 2 hours and 45 min).