[Loadstone] West bound inconsistency in exploration mode.

Kerry and Gemma Hoath kerryandgemma at gotss.net
Tue Feb 13 07:53:23 GMT 2007


        This raises an interesting point I have been wondering about for 
quite some time.
If one wanted to become a developer and assist with potential code 
improvement how would one go about this?
Which c compilers do we need to obtain, do they cost money and who do we buy 
them from?
I have often wanted features in loadstone which I am able to implement 
myself, providing patches for consideration in future versions.
Regards, Kerry.

----- Original Message ----- 
From: "Shawn Kirkpatrick" <shawn at odyssey.cm.nu>
To: "General discussion pertaining to the Loadstone GPS program" 
<loadstone at loadstone-gps.com>
Sent: Tuesday, February 13, 2007 4:05 PM
Subject: Re: [Loadstone] West bound inconsistency in exploration mode.


> Ok, this one's a confirmed bug. The angle is being calculated wrong if the
> points are in an exact straight line going due west. In this case the
> direction is being calculated as due east. This took a bit to track down 
> but
> the problem should now be fixed. The fix will be in the next version.
>
> On Mon, 12 Feb 2007, Geoff Waaler wrote:
>
>> Hi Shawn,
>>
>> Thanks much for the reply.  My purpose in including the coordinences of 
>> the
>> points in question was to show that they were not at an angle.  Even if 
>> they
>> were I do not believe its unreasonable to expect consistency between east
>> and west bound traversals.  If I'm experiencing rounding errors because 
>> of
>> my phone's limited computational skills why do they not occur during East
>> bound calculations?  If this is do to the points being at an angle, 
>> please
>> take a look at the data I provided and let me know how/why the points in
>> question are not considered due East/West from one another?
>>
>> Thanks again.
>> Geoff
>>
>> ----- Original Message -----
>> From: "Shawn Kirkpatrick" <shawn at odyssey.cm.nu>
>> To: "General discussion pertaining to the Loadstone GPS program"
>> <loadstone at loadstone-gps.com>
>> Sent: Monday, February 12, 2007 4:37 AM
>> Subject: Re: [Loadstone] West bound inconsistency in exploration mode.
>>
>>
>> This problem is somewhat common. It happens when points are off at an 
>> angle
>> from each other. The points you're talking about can probably be found if
>> you use north west or south west. What loadstone does is calculate the
>> distance and angle from one point to another. It breaks the circle up in 
>> to
>> 8 sections and tries to find a point in the section you want. Sometimes a
>> point will be close but just outside the calculated section. The
>> calculations should be the same for the opposite direction but doesn't
>> always seem to be the case. The only reason I can think of for this is 
>> that
>> maybe we're getting rounding errors with the floating point number
>> calculations. The phone isn't very good at these so that's very possible.
>>
>> On Mon, 12 Feb 2007, Geoff Waaler wrote:
>>
>>> Hi y'all (and since I live 35 degrees and change North I get to say
>>> this!!),
>>>
>>> I finally put together a test case documenting what I believe to be a 
>>> bug
>>> in
>>> loadstone when it calculates the nearest point to the West in 
>>> exploration
>>> mode.  I am running the "all other phone models" 0.66 version of 
>>> loadstone
>>> dated 2/1/07 on a Nokia 6682.  In case it matters my 6682 is locked to
>>> Cingular with the latest available firmware (4.65).
>>>
>>> I obtained pointshare data for a five mile area around latitude 41.9709,
>>> longitude -87.7018.  My last_position file points to: 
>>> 41.99152,-87.655756
>>> which in English translates to a hundred yards North of Sheridan Rd. and
>>> Thorndale in Chicago, IL.
>>>
>>> When I begin exploration mode and press the 8 key I am taken to 
>>> Thorndale
>>> and Sheridan as expected.  When I press the four key two blocks are
>>> skipped
>>> which will be found on the way back east.  Here are the relevant
>>> coordinances:
>>>
>>> Eastern point is Sheridan Rd. and Thorndale = 41.990431, -87.655756
>>> First block West is Kenmore and Thorndale = 41.990431,-87.657156
>>> Second block West is Winthrop and Thorndale= 41.990431,-87.658556
>>> Third block West is Broadway and Thorndale = 41.990231,-87.660656
>>>
>>> As you can see Thorndale avenue follows a direct latitudinal line for
>>> those
>>> two blocks where the points are missed during west bound exploration.
>>> Thorndale avenue drifts a little South when intersecting with Broadway.
>>> Of
>>> course we are relying on the accuracy of data pointshare managed to
>>> obtain,
>>> but for our purposes it serves to illustrate the problem.  I believe 
>>> that
>>> since the six key locates those two points during the virtual East bound
>>> trip from Broadway it would be reasonable to expect the West bound trip
>>> from
>>> Sheridan to land on those points also.
>>>
>>> Thanks for putting together a great software app!!
>>> Geoff
>>>
>>> _______________________________________________
>>> Loadstone mailing list
>>> Loadstone at loadstone-gps.com
>>> http://www.loadstone-gps.com/mailman/listinfo/loadstone
>>>
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