Geolocation
Geolocation is the technique of determining a user’s geographic latitude, longitude and, by inference, city, region and nation. There are a number of ways to do this: one of the common ones discussed on the internet (according to a Google search for “geolocation”, as we all know Google is the Answer) is geolocation via IP address. The kind I’m interested in is much more accurate: geolocation via GPS device.
I want to be able to know where I am. I want this for a lot of reasons, most of them geeky rather than actually reasonable. However, it would be nice to offer more specific statistics on where my pictures are actually taken with fine grain granularity that a GPS can offer. Additionally, some of my alternative projects – cell based geolocation and the like – could benefit from actual coordinates on which to base everything from restaurant locations to searches. Openguides is, in particular, one area that could benefit from this.
I want something that works over bluetooth. My laptop and phone both speak bluetooth, and something with an actual display is out of my price range, for the most part, so I want something I can use my phone to get data out of. (USB / serial obviously doesn’t work for that.) From what I understand, most GPS devices which support NMEA are going to work okay for communication, as there are tools out there which support them. (Whether I can get the thing to talk over bluetooth is a different concern, but one I’m becoming more proficient at every day.)
For a long time, all I could find for Bluetooth GPS devices were 200-250 USD and up. However, while discussing it with someone in #mobitopia on Freenode, I found the Delorme Bluelogger, a Bluetooth GPS device for $150. Matt already posted about our discussion, but I hadn’t yet.
I have some cash left over from Christmas, and I know that I almost never actually buy anything for myself. So, I’m going to splurge, and I’m going to get it. I’m going to learn to use it, and I’m going to do all kinds of neat things with it. Plans include:
- GPS Annotation of Photos – This rolls into my photo annotation project, and is part of the reason I was keen to get it done: I want to actual have some fun queries for normal people (rather than just RDQL-aware people) over my photos.
- Location Based Description of things for Openguides – Describing where things are with GPS coordinates allows searches by distance. Once I have that, the guide allows more niftyness.
- Association of Cell IDs to Geo locations – Tied to the previous, this allows me to know where I am based on a Cell ID: Useful for “what’s nearby”, as well as useful for the general “where are you” that I like to be able to do – with just my cell phone.
All in all, some of the apps I have in mind seem nifty, some geeky, some just demonstrative of something bigger. Some are RDF related, some are just fun. The Bluelogger seems like a decent tool to achieve everything I need to.
January 3rd, 2005 at 3:50 am
When I started work on this sort of thing for my photo annotations, I began with the Census Bureau’s U.S. Gazetteer Files. I used the ZIP Code file, but the Places file might work just as well. I imported all of this into a database, and wrote a few lines of code to give me back a place name given the distance from a specific lat/long.
Be aware, however, that there are lots of places that aren’t in those Census data files. I’ve resorted to entering problem spots by hand, but scouring for more sources of data might be best in the long run. (Maporama has been invaluable in pinpointing out-of-the-way places, like Girdwood, AK).
Exporting all of this data as RDF might be nice, but practically, I’ve found that it needs to be in a database meant for this type of querying, and I’m not sure any of the existing triplestore/query engines are up to the task just yet (i.e. no redland-mysql love here). Also, using mysql’s r-tree support might benefit a query engine here, but I haven’t looked into that much just yet.
Good luck with this project. If you approach this with the same energy as you’ve done with past projects, I’ll wait expectantly for some amazing results!
February 26th, 2005 at 9:24 am
Bear this in mind: digital cameras record a timestamp with every photo taken and GPS units store their track data with timestamps. What that means in practice is that, if you sync the clock in the camera with the GPS, you can wander around with a digital camera and GPS taking pictures as you go and then later on you can work out where the pictures were taken by comparing the timestamp on the image with the timestamped location data from the GPS.
June 24th, 2005 at 10:41 pm
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