Hi WanMil, I see that shapes created from precompiled sea are merged, so it works in general. The problem remains that for low resolutions I have to merge the shapes before the coords are rounded. So, for low resolutions the shape merger stops too early, because it will not create shapes with > 250 points as long as we use the java.awt.geom.area to split those shapes, and the merger doesn't know the result of the RoundCoordsFilter which typically reduces the number of points drastically for low res. Gerd
Date: Thu, 16 Jan 2014 12:09:17 -0800 From: gpetermann_muenchen@hotmail.com To: mkgmap-dev@lists.mkgmap.org.uk Subject: Re: [mkgmap-dev] shape merger in high-prec-coord branch
Hi WanMil,
yes, a few more shapes were be merged because of this change. Only if the parts go into different sub divisions they are not merged. I am not sure if that works for precompiled sea data, I'll verify that tomorrow.
Gerd
WanMil wrote
Hi Gerd,
good! This is the first part of my idea. Additionally I thought about what you have written as TODO: maybe better merge here? I think when cutting multipolygons it often happens that there are parts cut off that needn't be cut. I have attached a screenshot of a sea tile where I have colored some polygons in blue that could be merged to one big polygon. Maybe there is an advantage that some of the small cuts do not disappear on lower zoom levels because they belong to a bigger polygon.
But I am not sure if that isn't already solved by your changes.
WanMil
Hi WanMil,
please check the changes in r2970 reg. MultiPolygonRelation. Is this the change you had in mind?
Gerd
Date: Wed, 15 Jan 2014 21:55:17 +0100 From:
wmgcnfg@
To:
mkgmap-dev@.org
Subject: Re: [mkgmap-dev] shape merger in high-prec-coord branch
I think the artifacts are created by the rounding that happens when we convert from or to java.awt.geom.Area.
Yes. After the multipolygon splitting only the first and the last point of a common edge of two polygons can be a point that is added artificially. It sounds possible to detect if it ca be removed.
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