0m elevation contour lines aren't drawn

[gristlyanemone]

In the area https://opentopomap.org/#map=13/46.41029/45.03236 you can see 10m, 20m (passing through village Элвг) etc. contour lines at southwest and -10m at northeast (after lake Конурка), but no 0m contour line in between. Neither it appears at higher or lower scales.

Update. Better seen in Sea of Galilee area https://opentopomap.org/#map=17/32.75159/35.55457. The missing contour line is clearly noticeable on the uniform slope.

[gristlyanemone]

@sletuffe I think the 0m contour lines were hidden because in most cases they duplicate (and interfere with) shorelines. Possibly the better solution would be to enable the 0m contour lines only for selected areas (https://en.wikipedia.org/wiki/List_of_places_on_land_with_elevations_below_sea_level). I believe the areas could be defined as simple geographic quadrangles, i. e. by a pair of longitudes and a pair of latitudes. There are not many areas of interest in the list: some are duplicated, some have features in them listed separately, some are covered by ice, many are less than 10 meters shallow (but probably still worth to include).

[sletuffe]

@gristlyanemone I haven't thought about that. On one hand, this creates weird lines in the sea where the sea level is roughly at 0m:

But explicitly removing 0m lines is strange at below sea level places like you mentionned.

Another option to at least avoid contours line in the sea would be to draw sea polygons over contour lines.

[gristlyanemone]

Drawing sea polygons over contour lines is a good option for now.