[mkgmap-dev] [Patch v1] differet Coord implementation

Tue Mar 14 17:09:36 GMT 2017

Hi Gerd

Here is combined patch based on current trunk.

I haven't been through WrongAngleFixer in any detail yet.

Ticker

On Tue, 2017-03-14 at 15:30 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> I waited for further feedback from you. Please post your modified
> version or a patch.
> 
> Gerd
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> Gesendet: Dienstag, 14. März 2017 10:53:43
> An: mkgmap-dev at lists.mkgmap.org.uk
> Betreff: Re: [mkgmap-dev] [Patch v1]  differet Coord implementation
> 
> Hi Gerd
> 
> Are you still planning to implement this patch. I've been using it
> for
> a while with some additional changes and I didn't have any problems.
> I
> think it is tidier and makes things more obvious.
> 
> The addition changes I had were roughly as I listed in a follow-up:
> 
> ... much clearer and have the same effect if
>  imgFmt.Utils.toMapUnit
>  new:Coord.toHighPrec
> were re-coded as
>   return Math.round(degrees / 360.0D * (1 << resolution))
> 
> imgfmt.Utils.roundup()) change to rounding to nearest integer rather
> than being like ceiling():
>         public static int roundUp(int val, int shift) {
>                 if (shift <= 0)
>                         return val;
>                 return (((val >> (shift-1)) + 1) >> 1) << shift;
>         }
> 
> 
> In the new versions of Coord.getLatitude/Longitude(), could have/use
>         final int DELTA_HALF = 1 << (DELTA_SHIFT - 1);
> ...
>         public int getLatitude() {
>                 int lat24 = (latHp + DELTA_HALF) >> DELTA_SHIFT;
> ...
>         public int getLongitude() {
>                 int lon24;
>                 if (HIGH_PREC_BITS == 32 && lonHp ==
> Integer.MAX_VALUE)
>                         lon24 = (lonHp >> DELTA_SHIFT) + 1;
>                 else
>                         lon24 = (lonHp + DELTA_HALF) >> DELTA_SHIFT;
> ...
> 
> Ticker
> 
> On Fri, 2017-02-24 at 15:27 +0000, Gerd Petermann wrote:
> > Hi programmers,
> > 
> > 
> > After writing my findings here
> > http://www.mkgmap.org.uk/pipermail/mkgmap-dev/2017q1/026317.html
> > I did some cycling and decided that I might still be better to use
> > the attached patch.
> > 
> > It works better with 32 bits and is probably a bit easier to
> > understand. The major difference is
> > that it calculates the Garmin position of a point from the already
> > rounded 30 (or 32 bit) value.
> > In some cases this means that points in the map move by one, e.g.
> > one with 52.2452629, 21.0833536
> > 
> > appears on the right grid point instead of the left (it is very
> > close
> > to the middle).
> > 
> > Gerd
> > 
> > _______________________________________________
> > mkgmap-dev mailing list
> > mkgmap-dev at lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
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