Re: [talk-au] Draft association rules + LC page
2009/9/20 John Smith deltafoxtrot...@gmail.com: https://docs.google.com/Doc?docid=0AZf0jIYShBc0ZGNicXR6OXZfMGdoOGsycGZihl=en I've made some more tweaks to the above document, I've also had some private emails from people indicating they think this is a good idea and we should start thinking about taking the next move. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
[talk-au] new toy found by son
http://www.sparkfun.com/commerce/product_info.php?products_id=8725 ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 Liz ed...@billiau.net: http://www.sparkfun.com/commerce/product_info.php?products_id=8725 I've played with the accelerometer on the android handset I have, it can do 20 or 30 updates per second depending how busy the CPU is with other interupts. I tried to use it to augment GPS data but the math ended up doing my head in so I'm not sure how much use this would be compared to a 4 or 5Hz GPS logger alone unless someone is super duper at velocity math that is. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
On 01/10/2009, at 8:53 PM, John Smith wrote: I tried to use it to augment GPS data but the math ended up doing my head in so I'm not sure how much use this would be compared to a 4 or 5Hz GPS logger alone unless someone is super duper at velocity math that is. It wouldn't be too hard, just double-integrate the acceleration to produce a plot of your relative position. Attaching it to the stand and end points of the GPS trace should remove the zeroth order accumulation errors, and then you can start to play around with more fancy things using intermediate GPS data to adjust for non-linearities in the accelerometer readings. I did pretty much this in one dimension for a physics prac a few year ago at uni :) ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 James Livingston doc...@mac.com: On 01/10/2009, at 8:53 PM, John Smith wrote: I tried to use it to augment GPS data but the math ended up doing my head in so I'm not sure how much use this would be compared to a 4 or 5Hz GPS logger alone unless someone is super duper at velocity math that is. It wouldn't be too hard, just double-integrate the acceleration to produce a plot of your relative position. Attaching it to the stand and end points of the GPS trace should remove the zeroth order accumulation errors, and then you can start to play around with more fancy things using intermediate GPS data to adjust for non-linearities in the accelerometer readings. I did pretty much this in one dimension for a physics prac a few year ago at uni :) Here's the link to what I was playing with before, feel free to fill in the missing blanks, starts about here: http://forum.xda-developers.com/showthread.php?t=484610page=12 ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
There's only so much gain you can get out of a GPS antenna. Basically the best you can do to cover the whole sky (ie:180 degrees x 360 degrees) is 3dBi (double the power from a perfect isotropic antenna). Certainly you could design an antenna which had a reduced coverage, such as a cone, but it will always be a compromise between satellite count and gain. But saying that most GPS antennas are pretty poor performers, particularly the small patch antennas which are surrounded by metal shielding/PCB traces etc in the unit. For reference, given that the GPS signals are ~1.3GHz (Wiki says they span from 1176.45MHz to 1575MHz) an ideal dipole antenna would be 11.5cm long. A Dipole has a peak gain of 2.7dBi (I think, it's about that). Anyway. I wonder how much use accelerometers would be on a MTB? You experience lots of impulse forces (forces which act over time scales much shorter than the sampling rate of the accelerometer, ie: beyond it's nyquist limit) and so the integration would be seriously inaccurate. Accelerometers would be an excellent solution for mapping tunnels though. Especially since you're only talking about a short-ish time span and you can potentially have 2 accurate calibration points (one at each end of the tunnel). I guess if the accelerometer could be mounted in some form of suspended cage to dampen high frequency noise it would be quite accurate. /ramble -Brent - Original Message - From: John Smith deltafoxtrot...@gmail.com Date: Thursday, October 1, 2009 9:58 pm Subject: Re: [talk-au] new toy found by son To: Liz ed...@billiau.net Cc: talk-au@openstreetmap.org 2009/10/1 Liz ed...@billiau.net: he was hoping that gps+accelerometers+gyros would provide accurate cheap mapping of mtb trails Why not just build/buy a better antenna for the GPS? The higher the gain the better the accuracy etc, most GPS antenna are tiny so if you make a massive one you should get good readings :) ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 Elizabeth Dodd ed...@billiau.net: The higher the gain the better the accuracy etc, most GPS antenna are tiny so if you make a massive one you should get good readings :) because he wants a degree in surveying, that's why so he has to produce something new / different Oh that's easy then, get him to figure out how to semi-sync with the secondary GPS frequency, which is what high end surveying equipment does, you don't need to lock onto the signal, just get close enough to calculate the atmospheric effects on the L1 signal, and do it cheaply enough we can get less than 1m accuracy with consumer grade kit :D ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 b.schulz...@scu.edu.au: Accelerometers would be an excellent solution for mapping tunnels though. Especially since you're only talking about a short-ish time span and you can potentially have 2 accurate calibration points (one at each end of the tunnel). I guess if the accelerometer could be mounted in some form of suspended cage to dampen high frequency noise it would be quite accurate. Or just use a phone with AGPS from the phone network, when I have 3G connectivity on the phone I usually get 2m accuracy and works inside buildings etc. Now we just need 3G connectivity Australia wide :D ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
On Thu, 1 Oct 2009, John Smith wrote: Oh that's easy then, get him to figure out how to semi-sync with the secondary GPS frequency, which is what high end surveying equipment does, you don't need to lock onto the signal, just get close enough to calculate the atmospheric effects on the L1 signal, and do it cheaply enough we can get less than 1m accuracy with consumer grade kit :D he's not using a D-GPS setup -- Be careful of reading health books, you might die of a misprint. -- Mark Twain ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 Elizabeth Dodd ed...@billiau.net: On Thu, 1 Oct 2009, John Smith wrote: Oh that's easy then, get him to figure out how to semi-sync with the secondary GPS frequency, which is what high end surveying equipment does, you don't need to lock onto the signal, just get close enough to calculate the atmospheric effects on the L1 signal, and do it cheaply enough we can get less than 1m accuracy with consumer grade kit :D he's not using a D-GPS setup Using both GPS freq's isn't D-GPS, the biggest unknown with the regular GPS signal is delays in the ionosphere, being able to establish that using the secondary/military GPS freq takes out the uncertainity and you get a much more accurate signal ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
On Thu, 1 Oct 2009, John Smith wrote: On Thu, 1 Oct 2009, John Smith wrote: Oh that's easy then, get him to figure out how to semi-sync with the secondary GPS frequency, which is what high end surveying equipment does, you don't need to lock onto the signal, just get close enough to calculate the atmospheric effects on the L1 signal, and do it cheaply enough we can get less than 1m accuracy with consumer grade kit :D he's not using a D-GPS setup Using both GPS freq's isn't D-GPS, the biggest unknown with the regular GPS signal is delays in the ionosphere, being able to establish that using the secondary/military GPS freq takes out the uncertainity and you get a much more accurate signal because i proof read and edit the manuscripts i get all of this already, however it ain't accurate enough in heavy vegetation cover or any of the usual places where mtb trails are -- BOFH excuse #104: backup tape overwritten with copy of system manager's favourite CD ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/1 Elizabeth Dodd ed...@billiau.net: On Thu, 1 Oct 2009, John Smith wrote: On Thu, 1 Oct 2009, John Smith wrote: Oh that's easy then, get him to figure out how to semi-sync with the secondary GPS frequency, which is what high end surveying equipment does, you don't need to lock onto the signal, just get close enough to calculate the atmospheric effects on the L1 signal, and do it cheaply enough we can get less than 1m accuracy with consumer grade kit :D he's not using a D-GPS setup Using both GPS freq's isn't D-GPS, the biggest unknown with the regular GPS signal is delays in the ionosphere, being able to establish that using the secondary/military GPS freq takes out the uncertainity and you get a much more accurate signal because i proof read and edit the manuscripts i get all of this already, however it ain't accurate enough in heavy vegetation cover or any of the usual places where mtb trails are What about designing a portable D-GPS unit? These you can get to transmit, and add either bi-directional amps or bigger antenna, you just put 2 or 3 of them up and then use a wifi device based device, like a phone, to figure out it's position. Although if you used 900Mhz band instead of 2.4Ghz you'd have greater range. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
John Smith deltafoxtrot...@gmail.com wrote: Or just use a phone with AGPS from the phone network, when I have 3G connectivity on the phone I usually get 2m accuracy and works inside buildings etc. Now we just need 3G connectivity Australia wide :D I thought AGPS didn't help with accuracy, it just helps with faster satellite aquisition by downloading ephemeris data instead of searching blindly for visible satellites. It won't help with surveying a tunnel. -- Sam Couter | mailto:s...@couter.id.au OpenPGP fingerprint: A46B 9BB5 3148 7BEA 1F05 5BD5 8530 03AE DE89 C75C signature.asc Description: Digital signature ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] new toy found by son
2009/10/2 Sam Couter s...@couter.id.au: I thought AGPS didn't help with accuracy, it just helps with faster satellite aquisition by downloading ephemeris data instead of searching blindly for visible satellites. It won't help with surveying a tunnel. Depends what type of AGPS I think, in the case of phone networks they potentially know your location to within a couple of metres and could either ignore or supplement anything the phone sends with what the phone network already knows about your position. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] OSM Client for Symbian?
I've been using Mobile Trail Explorer on my E71. http://www.substanceofcode.com/software/mobile-trail-explorer/* *It's far from polished, crashes occasionally, and has a flakey UI, but it records traces to KML and GPX, and can load OSM map tiles if you have a Internet connection. I believe you can also download the map tiles to a cache so as that you can use them without Internet, but I've not tried it.* *But, save your trace frequently, and don't dare interrupt saving a trace, lest it eat all your hard work and crash... Hope this helps, Jason* * 2009/10/2 Cosmic Charade cosmichar...@gmail.com I have a Nokia N95. I want to go walkabout north side Canberra this weekend to get some fresh air. I'm ready to go with a stack of batteries and plenty of music. a) Is there a Symbian / Nokia client to access OSM on the go like I can do with Google Maps? b) Can I record a track with say Nokia Sports Tracker that can export tracks to kml format to contribute if I find any bike or walking tracks or POIs along the way? My wife stole the netbook so I can't use that with my GPS dongle :-( Thanks.. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] OSM Client for Symbian?
It also takes waypoints which is extra useful if you're going to use it to contribute to OSM. On Fri, 2009-10-02 at 12:01 +1000, Jason Stirk wrote: But, save your trace frequently, and don't dare interrupt saving a trace, lest it eat all your hard work and crash... Even better, turn on the GPX stream feature and it'll write your trace to a GPX file in real time, so if it crashes it can resume/restore the data. I find it's generally a quite solid app, if a little resource hungry. My main problem is that my phone runs out of memory and starts randomly closing things if I try to do too much. Cheers, Ash. -- Ashley Kyd • Web Software Development in Brisbane, Australia. • Phone (07) 3129 2332, or visit http://kyd.com.au/ signature.asc Description: This is a digitally signed message part ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] OSM Client for Symbian?
thanks for that.. so a 'waypoint' is used for POI contribution? The OSM maps also have bike and walking trails which Google Maps and Nokia Maps don't so for my purposes I actually require mobile OSM tomorrow. Nokia Sports Tracker can save and export tracks to kml so I may just use that for traces as I will have it on anyway. Ashley Kyd wrote: It also takes waypoints which is extra useful if you're going to use it to contribute to OSM. On Fri, 2009-10-02 at 12:01 +1000, Jason Stirk wrote: But, save your trace frequently, and don't dare interrupt saving a trace, lest it eat all your hard work and crash... Even better, turn on the GPX stream feature and it'll write your trace to a GPX file in real time, so if it crashes it can resume/restore the data. I find it's generally a quite solid app, if a little resource hungry. My main problem is that my phone runs out of memory and starts randomly closing things if I try to do too much. Cheers, Ash. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] OSM Client for Symbian?
Did you have to do anything to get it to work and find your GPS? It says GPS not found in the settings (Nokia N95) Jason Stirk wrote: I've been using Mobile Trail Explorer on my E71. http://www.substanceofcode.com/software/mobile-trail-explorer/* *It's far from polished, crashes occasionally, and has a flakey UI, but it records traces to KML and GPX, and can load OSM map tiles if you have a Internet connection. I believe you can also download the map tiles to a cache so as that you can use them without Internet, but I've not tried it.* *But, save your trace frequently, and don't dare interrupt saving a trace, lest it eat all your hard work and crash... Hope this helps, Jason* * 2009/10/2 Cosmic Charade cosmichar...@gmail.com mailto:cosmichar...@gmail.com I have a Nokia N95. I want to go walkabout north side Canberra this weekend to get some fresh air. I'm ready to go with a stack of batteries and plenty of music. a) Is there a Symbian / Nokia client to access OSM on the go like I can do with Google Maps? b) Can I record a track with say Nokia Sports Tracker that can export tracks to kml format to contribute if I find any bike or walking tracks or POIs along the way? My wife stole the netbook so I can't use that with my GPS dongle :-( Thanks.. ___ Talk-au mailing list Talk-au@openstreetmap.org mailto:Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
