brightkite, foursquare, Geek Stuffs, gowalla, gps, LBS, loopt

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Location-based service(LBS) is an information or entertainment service offered based on a location of a particular person – commonly utlizing the ability to access geographical location using a particular device such as mobile phone.

Geographical location of a particular person can be identified by using three methods

  • Mobile Network Based
  • Device Based
  • Hybrid


Mobile Network Based means that the location of the device is identified by getting the location of radio cell. This will heavily depends on the location of the service providers network infrastructure.The accuracy of the method varies, depending on whether it uses cell identification or triangulation of multiple cell towers. Factors such as the concentration of the base station will affect the accuracy, for example in urban areas, the cell concentration is much higher thus the information will be much more accurate.

GPS Based means that the location of the particular device is obtained by utilizing the GPS technology. This will mean that the device will need to have a software and hardware to obtain the satellite signal as well as sufficient battery to maintain the lock. The key disadvantage of this method is that the battery life of the particular device will be severely affected as GPS is known to use a lot of power. In addition to that, it can take quite a long time to obtain a lock to several GPS satellites in order to get the proper triangulation and accuracy. This is the case as the device will need to roam to see which of the “birds” is available in to give the GPS signal locking.

Hybrid means that the location of a particular device is obtained by utilizing both the Mobile Network as as the GPS. This is usually known as assisted-GPS. Assisted-GPS used the best of both world where by it first obtains the approximate location of a particular device using Mobile Network. And from there, the location of the “available” locked satellites is obtained via the data channel. Then, the device will try to get a lock signal with the satellites. This address the problem of roaming and testing to see which are the satellites which is available to give the proper location at a particular area. This method of course addresses the locking issue, but it will require the phone to have data service as it will need to obtain satellite information via the mobile data network.

Location based services, as it further defined in social network space is an interactive service between different parties based on the location information. For example, two friends can share information on the best place to eat Steak in say, Singapore’s Orchard Road. or the best bagel on fifth avenue in New York city. Its typically being misconstrued as way for “Internet” companies to track where a person is. Yes, by the look at what the technology can offer – it can really do that now. But if one were to examine how it application works, LBS will require the user to “push” for location instead of the other way around. Thus, its not the case of tracking – but its the case of reporting the location. This is different from the services that is offered by Google Latitude, where the location is pushed to the server. But even with that, there are option for the user to push the location.

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Privacy issues will continue plague the growth of location based services – as location based services means that one would be sharing their location with a third party. In order to overcome this issue, there must be some sort of level of trust that needs to be built between the service provider and the user. In addition to that, the user should also be aware of the risk that need to be taken when joining any location based service.

The following image compares the different type of Location Based Services.

Infographic matrix: Foursquare vs Facebook vs Gowalla vs Yelp vs BrightKite vs. Where.com vs Booyah vs. Loopt comparison guide
Please click on the image for a big picture!

Apple, Geek Stuffs, geotag, gps, gpsbabel, gpsphotolinker, lightroom, Mac, Photography

Geotagging is process of tagging your photos to the GPS coordinate of your camera – and of course you lah (assuming you are taking the photos). There are a lot of ways of geotagging, from using purpose built device (Nikon GPS) to connecting your camera to GPS devices (via MC-35 cable) to using post-capture geotag.

Personally, I have tried pretty much all the method above, and realised that for a street shooter like me, post capture geotag is probably the best way to go about it. Post capture geotag means that the geotagging process is done after you capture the photos. Whereby, the GPS tracklog captured using a gps device is merged together using software (that you can get of the internet!).

Things that you will need for post-capture GPS device:

  • Camera (time synced to UTC time)
  • GPS Logger (e.g. Sony GPS-CS1)
  • Geotagging Software

I am currently using Sony GPS-CS1 as shown below:

gps-cs1.jpeg

Reason being is because, i got it cheap of the Buy Sell Thread 😀 Other than that, you can just buy other loggers like Holux or even GPS devices that supports track logs like Garmin Colorado (bulky though). GPS CS-1 is normally hooked to my bag via a carabiner.. and its so so easy. It uses normal battery thus no problem when it comes to ensuring you have enough battery (GPS devices are power hungry!).

So.. when you go out and shoot.. you just shoot and then make sure you switch on your GPS logger. What the logger does is to store your GPS coordinates inside the data storage (within the logger).

Assuming you have done the above.. now you are back home, showered and ready to look at your photo.. here are step by step on how you geotag (post capture way).

Step 1 – Converting your logsCopy the track logs from your logger to your Mac. Once you copied, the next step is to convert to the log files to a format which is understood by the software that we going to use. The software which i use is GPSPhotoLinker (its free) and can be downloaded from http://www.earlyinnovations.com. Why this software? Because its free.. he he..
The problem with GPS CS-1 is that the log file is NMEA, and not understood by GPSPhotolinker which uses GPX formatted files. Some loggers might use GPX format so you can skip the conversion process. Other softwares like HoudahGps also supports NMEA, but i refuse to pay for somethings which i can download for free :p
So to convert, you would need gpsbabel – get it from http://www.gpsbabel.org/. Download the one with the GUI so that it’ll make your like much easier 😀
So once you configured, just open GPS Babel.. and set the settings as per the image below…

gpsbabel-convert-to-gpx.png
Press save file.. and you will get the GPX file.

Step 2 – Load the tracks to GPSPhotoLinker

Easy! Just press the Load Tracks button.. and choose your GPX file!

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Step 2 – Load the photos to GPSPhotoLinker

Loading photo is even easier! You can either use the button Load Photos, or you can just drag the photos from Lightroom or which ever folder to the rectangle space on the right!

gpsphotolinker-loadphoto.png
You would be able to see the file on the right side. And you can see the location information 😀

Step 4 – Save the metadata

Next! Just go to the Auto tab and press Batch save to photos!

gpsphotolinker-savetophoto.png
You are done!

Step 5 (Optional) – Reload metadata in Lightroom

I use Lightroom, so i would need to reload the metadata. Easy.. Menu –> Metadata –> Read Metadata From Files


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By now, your photo is already linked! and ready to go.. If you see from lightroom, the Exif would have loaded your GPS data and you can do what ever you want!


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I hope the guide is clear. Feel free to buzz me if you need more information!