Andy Crowther wrote:I wondering if anyone can point me in the direction of how I would allow users to use a 3rd party GPS receiving to report their location to my app?
I read on SO that it might involve parsing NMEA? Can anyone give me a few more pointers of where I should look?
Most GPS receivers support NMEA 0183. There is a LGPL Java parser library called Java Marine API on GitHub - it may do which you are looking for.
Your "app" is a Java app, right? Not Android, for example?
Note to self: Time to write a test program.
How accurate do you think the GPS device will be? Will it be better than 10 meters?
An interesting article: http://www.andygup.net/how-accurate-is-android-gps-part-2-consuming-real-time-locations/
Unfortunately, me being still a beginner (maybe 4 months in?) it still takes me a very long time to understand new things like this... and this is just added to my list of things to learn Hopefully by next March or so, as people start doing track days again, I'll have figured it out
Norm Radder wrote:Taking fixes while standing still will show you a circle of fixes that would give you an idea of what kind of accuracy you can get.
Modern GPS devices with smoothing software can probably show points on a reasonable track when moving at speed.
That could be so, but I wouldn't just assume that. Here's my experience with GPS devices moving at speed:
I'm a birder, and sometimes I see a bird while riding on a bus and I want to record its species and location for eBird. The location part isn't easy, especially if you're far from landmarks, so my idea was to use my camera, which has built-in GPS. I can set it to record the location in the metadata of the photographs, so I did that. It's not straightforward to get the location out of the metadata, you have to get software which can do that, but it's certainly not difficult either. So what I expected was a photo of blurry roadside vegetation with the GPS location stamped into the metadata.
But when I got home and looked at the photos, none of the ones from the moving bus had the location in the metadata. All of the photos I took when standing still did have the location in the metadata. So I'm assuming that the camera's GPS doesn't function when it's moving at speed.
So clearly my camera's GPS doesn't have the smoothing software which Norm mentioned. Not really surprising, it's an inexpensive point-and-shoot. My point is that you should evaluate your chosen GPS device to see if it does work accurately at the speeds you're expecting.
ones from the moving bus
I'm often surprised that my current GPS can get a fix inside a vehicle. Some of my previous GPS devices had problems if they did not have a full, open view of the sky.
I'm not sure how well the signals from the satellites penetrate the metal tops/sides of a vehicle.
So I was wondering if the motion or being inside a bus was the problem.
Norm Radder wrote:So I was wondering if the motion or being inside a bus was the problem.
That's a good question. I was assuming that being inside the bus wasn't the problem because the viewfinder screen was showing the icon which confirms that the camera has a good GPS connection. Clearly I should try the experiment where I sit on top of the bus as it travels along the freeway, or where I get towed behind the bus on a skateboard, or something like that...
Anyway I assume that even GPS devices in today's phones can function at highway speeds because many cyclists use Strava to record their ride and that (as far as I know) works fine even when they descend at high speed.