Grid display

[josephbirkner]

For each map layer, it should be possible to display a tile grid for the currently active grid levels of that layer. This should also be remembered in the URl/local storage.

[MisterGC]

For each map layer, it should be possible to display a tile grid for the currently active grid levels of that layer. This should also be remembered in the URl/local storage.

Acceptance:

• Allow users to (de-)activate choose one grid visualization for each activated map feature layer
• Deactivatable grid label which shows by default the mapget grid number/coords (will be covered by 'Tiles as Features')
• Allow customization of displayed grid label e.g. for custom tile numbers (will be covered by 'Tiles as Features')
• ensure that visualization is a hairline, especially when zoom in close so that users can easily spot if some geometry
  starts/end on the border

Additional thoughts/ideas:

• grid visualization can be toggled and opacity can be controlled
• fade the grid out when invidual cells of the chosen level become too small to avoid confusing 'globe filled with grid-color'
• also (optionally) display next lower (e.g. 14) and higher (see sketch below) level but clearly show what the chosen reference level is

References:

• https://sandcastle.cesium.com/?src=Imagery Layers Manipulation.html

Ideas/Sketches:

The following sketch shows how we may display three tile levels at once with the chosen tile level being the one standing out most, the others just give some additional guidance - showing the tile id should be optional/toggable