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#271681 - 09/12/2005 00:25 navigation revisited
Daria
carpal tunnel

Registered: 24/01/2002
Posts: 3937
Loc: Providence, RI
Try out RoadNav (http://roadnav.sourceforge.net/). The navigation functionality is in a library released under the LGPL.

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#271682 - 09/12/2005 13:27 Re: navigation revisited [Re: Daria]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Quote:
Roadnav uses the free TIGER/Line files from the US Census Bureau to build the maps

Which we've determined doesn't have accurate enough data, missing things like one-way roads.
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Bitt Faulk

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#271683 - 09/12/2005 15:32 Re: navigation revisited [Re: Daria]
siberia37
old hand

Registered: 09/01/2002
Posts: 702
Loc: Tacoma,WA
Quote:
Try out RoadNav (http://roadnav.sourceforge.net/). The navigation functionality is in a library released under the LGPL.


Looks pretty sweet- have to check that one out. It will take some code examination to see if it's up to the challenge of running on the Empeg (with no Math Coprocessor!). And of course, Navigation will never be great with TIGER but I think we can always do our point-to-point directions with Google maps and be happy.

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#271684 - 09/12/2005 16:11 Re: navigation revisited [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
I seem to recall they said they also used a second data source in addtiion to Tiger. Perhaps it's worth a look.
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Tony Fabris

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#271685 - 09/12/2005 21:31 Re: navigation revisited [Re: siberia37]
siberia37
old hand

Registered: 09/01/2002
Posts: 702
Loc: Tacoma,WA
Quote:
Quote:
Try out RoadNav (http://roadnav.sourceforge.net/). The navigation functionality is in a library released under the LGPL.


Looks pretty sweet- have to check that one out. It will take some code examination to see if it's up to the challenge of running on the Empeg (with no Math Coprocessor!). And of course, Navigation will never be great with TIGER but I think we can always do our point-to-point directions with Google maps and be happy.


An examination of the code reveals lots of floating point operations- it's main base point unit seems to be represented by a double. This is opposed to RoadMap where the main base unit is an Integer- Roadmap isn't exactly quick, so I can't Imagine RoadNav would be doable on the Empeg. At least not without some code changes..

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#271686 - 09/12/2005 21:37 Re: navigation revisited [Re: siberia37]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Aren't there a whole lot of FP-to-Integer libraries that could be grafted in? I mean, yes, I know those aren't as fast as an FPU, but how much FP math are we talking about?
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Tony Fabris

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#271687 - 09/12/2005 23:51 Re: navigation revisited [Re: tfabris]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Quote:
Aren't there a whole lot of FP-to-Integer libraries that could be grafted in? I mean, yes, I know those aren't as fast as an FPU, but how much FP math are we talking about?

You can either let the kernel emulate the FP instructions or link in a library which handles it for you. Either one isn't going to be as fast as if you used integers in the first place.

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#271688 - 08/01/2006 04:26 Re: navigation revisited [Re: tfabris]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
User-space FP emulation is doable - I've even done in-kernel FP emulation on the empeg. You'd take the performance hit though if you're doing a lot of FP operations. I suspect that would be the case here.
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#271689 - 08/01/2006 13:10 Re: navigation revisited [Re: tfabris]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14493
Loc: Canada
The default Empeg and Hijack kernels already include floating-point support, emulated in software.

-ml

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#271690 - 08/01/2006 15:28 Re: navigation revisited [Re: mlord]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
So Derrick, how much FP are we talking about in that code?
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Tony Fabris

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#271691 - 09/01/2006 13:53 Re: navigation revisited [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
If the main unit is a floating point figure, as stated, I'd guess nearly all of them.
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Bitt Faulk

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