Creation of Maps: Rendering of lakes versus coast lines
  • In the "Test of Version Android 2.1.x" I mentioned that the IJsselmeer was disappearing and thought it was the new Android version, but it is a map creation bug. The map creation, and as a consequence the map rendering,  doesn't make a difference between (multi-)polygons tagged as lake and (multi-)polygons just tagged with a name or tagged with coast line.

    The IJsselmeer is disappearing on zooming out. The Bodensee is also disappearing on zooming out. And so are the big lakes in Sweden (Just downloaded and checked).

    It is logical that small lakes disappear on zooming out. However, Those big water masses like the IJsselmeer, the Bodensee, the big Swedish lakes are tagged otherwise because they are so big and need to stay visible because of their impact on the map and to keep as reference when zooming out, otherwise the map becomes unrecognizable. That's also how it is described in Openstreetmap (see natural=lake versus natural=coastline, although the coastline tag is changing in the last years).
    As far as I can judge now, Navigator doesn't make a difference between these variations. Therefore, the big lakes and inside seas are also disappearing on lower zoom levels thereby making the maps unrecognizable.

    And with regard to the Bodensee (Lake Constance): I did not have Switzerland installed. The lake is not rendered correctly and complete parts are missing. When zooming out the lake disappears partly and the Northern arm is not drawn at all. Also the parts of Germany and Austria are not correctly drawn.
    Then I downloaded Switzerland. Now the Northern arm is rendered, but that belongs to Germany (Baaden-Wurtenberg). So, why wasn't it drawn? With Switserland in place, the Bodensee is now correctyl rendered and also the Austrian (small) part, which map I did have installed.
    Upon zooming out the entire Bodensee disapears again like described above.
    So rendering of the Bodensee is buggy due to the multi-polygons not closed when crossing borders. Somehow the map creation needs to include the full (closed) polygons outside the country borders to beable to render such a lake in different countries correctly.

    (I did not check the lake Geneve (Lac de Lausanne) but I assume it is the same as the country border between France and Switzerland is running through the lake, and maybe the same for the big lakes between USA and Canada.
    Also: Do these big North American lakes disappear as well on zooming out?? I didn't check these either)



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  • Hello,

    We are aware of the problem. There are some possible solutions(adding big lakes to earth.mca etc..). I'm going to try them as soon as there is some time.

    This should also solve most of the problems with border-close lakes.

    Thanks for the long report.

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