[mkgmap-dev] patch to write polygons in decreasing order

Fri Nov 11 16:14:40 GMT 2016

Hi Ticker,

thanks for your work, I've committed it now with r3701.
I'll probably move calcAreaSizeTestVal() and roundPof2() to Utils tomorrow.

Gerd

Ticker Berkin wrote
> Hi Gerd
> 
> I think the reason why the buildings look different is because, without
> --order-by-decreasing-area, they get merged into a single area and then
> a filter (DouglasPeucker), finding the intermediate points are within
> the tolerance of a straight line, removes all but the 4 corners of the
> complete block. With --order-by, they are output individually as
> accurately as possible, but, because we are at/beyond at the limit of
> accuracy, rounding effects become obvious.
> 
> You mentioned GPSMapEdit not showing the smaller shape on top of the
> larger. Using it to look at your test case of buildings in Bremen, and
> the difference between with/without the option, I think it might apply
> the size rule itself - drawing smaller shapes on top of larger. The
> example I found was Penny supermarket @ 53.06650,8.79501 straddling a
> number of buildings. With the buildings merged, it is smaller and hence
> shows. With them separate, the buildings are smaller and they show.
> Does this fit with your observations? Which examples were you looking
> at? www.openstreetmap.org doesn't show Penny either.
> 
> I didn't use Util.roundUp because I wanted something to round to the
> closest power of 2 and it rounds up to the next power of 2. I've
> improved the javaDoc text for roundPof2.
> 
> I've made the other changes and attach a patch.
> 
> Regards
> Ticker
> 
> 
> 
> On Fri, 2016-11-11 at 11:37 +0000, Ticker Berkin wrote:
>> Hi Gerd
>> 
>> I'll check on the rounding, fix the warn>debug and add the pre-test
>> to
>> the splitting into areas.
>> 
>> I've just loaded GPSMapEdit and see what you mean about the long
>> lines
>> of buildings - they are wavy!. I'll work out why it is happening.
>> 
>> Regards
>> Ticker 
>>  
>> On Fri, 2016-11-11 at 01:25 -0700, Gerd Petermann wrote:
>> > Hi Ticker,
>> > 
>> > sorry, still some problems:
>> > 1) I think I found an error in method Area.roundPof2(int val, int
>> > shift)
>> > I wanted to find out why you did not use Util.roundUp(int val, int
>> > shift). 
>> > 
>> > For val=-9567 and shift=4 I see 
>> > -9568 from your routine and
>> > -9552 from the other
>> > So it seems your routine doesn't round up as the javadoc says. 
>> > So either the doc or the result is wrong.
>> > 
>> > 2) Please check the new log messages. The severity level warning
>> > should not
>> > be used for debug messages.
>> > A warning message should be understandable for the end user.
>> > 
>> > 3) Reg. performance:
>> > I think most of the area.intersect calls are not needed when you
>> > add
>> > this
>> > block at the beginning of
>> > splitIntoAreas():
>> > 		// quick check if bbox of shape lies fully inside one
>> > of the areas 
>> > 		for (int areaIndex = 0; areaIndex < areas.length;
>> > ++areaIndex) {
>> > 			if
>> > (areas[areaIndex].getBounds().contains(e.getBounds())) {
>> > 				used[areaIndex] = true;
>> > 				areas[areaIndex].addShape(e);
>> > 				return;
>> > 			}
>> > 		}
>> > 		// Shape crosses area(s), we have to split it
>> > 		// Convert to a awt area
>> >                ...
>> > 
>> > ciao,
>> > Gerd
>> > 
>> > 
>> > 
>> > 
>> > 
>> > --
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>> > -write-polygons-in-decreasing-order-tp5884038p5885742.html
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> sortAreas_v5.patch (36K)
> <http://gis.19327.n8.nabble.com/attachment/5885760/0/sortAreas_v5.patch>

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