Yellow Squares Appearing in Water Bodies at Certain Zoom Levels

[yuriiurshuliak]

Description

When viewing specific bay locations in the app (e.g., Tris Klissies Bay, Papas Bay, and the German Bight at light tower Roter Sand), graphical glitches occur at zoom levels 16, 17, 18, and 15. These glitches manifest as squares of yellow land extending into the water. The issue is most prominent in Tris Klissies Bay but can also be observed in other locations. It is most prominent at this location: https://osmand.net/map/#17/36.66918/25.38369.

Steps to reproduce

Steps to Reproduce:

• Open this location in the OsmAnd app: https://osmand.net/map/#17/36.66918/25.38369
• Check this bay on the map at different zoom levels (16, 17, 18)
• Observe the land squares of yellow extending into the water

Here’s a table summarizing the locations where the issue is reproduced, along with the corresponding zoom levels and links:

Location	Zoom Levels	Link
Tris Klissies Bay	16, 17, 18	Tris Klissies Bay
Papas Bay	18	Papas Bay
German Bight, Roter Sand	15	German Bight - Roter Sand

Actual result

When viewing the specified locations at various zoom levels, specifically 16, 17, and 18, there are graphical glitches where squares of yellow land extend into and appear in the water.

Expected result

The map should accurately render the coastline and water boundaries without any graphical glitches.

[yuriiurshuliak]

Related to osmandapp/OsmAnd#18593

[josail]

Thank you very much Yuri for this good summary of the issue!

[yuriiurshuliak]

The bug was partially reproduced. To replicate this issue, visit Tris Klissies Bay, Papas Bay, and the German Bight - Roter Sand and try zooming from level 15 to 18. In my experience, Tris Klissies Bay and Papas Bay do not display yellow squares at all zoom levels. However, as shown in the screenshots, the algae icons are significantly cropped. For German Bight - Roter Sand (53.85317° N, 8.08217° E), I could reproduce the error at zoom level 15, where yellow squares appear in the middle of the water.

OsmAnd~ 4.8.0#2643m, released: 2024-07-01

	Tris Klissies Bay

Papas Bay	German Bight - Roter Sand

[josail]

"the algae icons are significantly cropped", yes, but correctly according to their detailed shape in the OSM database. So the seagrass area fill pattern is displayed perfectly correct.

[josail]

@ Roter Sand @ Zoom 15 I could follow the yellow square pattern extensively west and south, including that at a south edge of the yellow squares, another rectangle consisting of yellow squares seemed to replicate the pattern of yellow square tiles in a rectangular shape, so there the glitch shows some symetrical order and is extending over multiple nautical miles...

[josail]

Issue 17851 appeard similar, perhaps related to the same cause for the display glitch. Maybe also the solution is similar?

[josail]

Perhaps helpful: The yellow squares problem continues to appear. However, if I switch from "nautical" rendering style to the "marine" rendering style proposed by Quantenschaum (see https://github.com/osmandapp/OsmAnd/issues/16894), this problem is not visible in the vicinity of the lighthouse Roter Sand in the German Beight. The other locations with yellow squares indicated in Greece still show the same yellow square problem. So changing the rendering style seems not to provide a general solution of the problem, but has partial influence on the problem.