[mkgmap-dev] line/polygon filters fix

Tue Mar 23 13:17:08 GMT 2021

Hi Gerd

I don't get any detectable failures, but this might cause difficulties
with adjacent junctions and/or housenumbers.

If there are two adjacent equal points, with the first not preserved
and the second preserved, the existing RemoveObsoleteFilter will
replace the first with the second and leave the second in as well. The
code clearly intended not to duplicate the preserved point, and, if
they were the other way around, doesn't.

Ticker

On Tue, 2021-03-23 at 12:38 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> please add a unit test that shows where the old code fails.
> 
> 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, 23. März 2021 13:10
> An: mkgmap development
> Betreff: [mkgmap-dev] line/polygon filters fix
> 
> Hi Gerd
> 
> I was trying to diagnose a problem with a repeating points in
> polylines
> as reported by GPSMapEdit and found a problem in
> RemoveObsoletePointsFilter where it duplicates a point.
> 
> Also in this and/or RoundCoordsFilter I've made some changes:
> 1/ stop the chain when polygons get too small
> 2/ keep polygons closed with the same first/last point
> 3/ slight logic tidy-up
> 4/ add a couple of debug lines to be consistent
> 
> Patch attached.
> 
> Actually these didn't make any difference to the repeating points
> problem. This happens when there are enough unused bits in the last
> byte of the polyline bitsteam to represent an extra point. I can't
> see
> any good way of stopping this.
> 
> Ticker
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