Custom ServiceImageTiledLayer zoom visibility

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07-23-2018 01:47 AM
OliverBoesche
New Contributor II

Hello,

for our software we had to implement an own ServiceImageTiledLayer foreach level of detail/ zoom levels. Therefore each tiles layer consist of a tile cache with only the top zero layer and not all detail layers in one cache. Hope that this is clear enough. Through our constraints it is not possible to put them all together in one custom layer instance.

The standard MapView behaviour is to make them visible and invisible on the different zoom levels according to an unknown decision metric based on resolution and scale from the LevelOfDetail. That works so far, if we add the caches in a sorted order according to the resolution of each cache. But then we see some problems to display them correctly to our requirements. I try to use practical words to avoid missunderstandings in the words. Please tell me if something isn't clear enough.

Problems:

  • Caches are automatically made invisible which allows gaps between the LoDs
    • IsVisibleOnScale is true for the whole zoom range
    • IsVisible is always on true
  • Min/MaxScale on a ServiceImageTiledLayer has no effect in this scenario

The desired behaviour:

  • Fully zoomed out => the topmost cache shall be visible
  • Fully zoomed in => the lowermost cache shall be visible
  • Between two overlapping caches the lower one shall be displayed

So, my question would be if it is possible to solve this issues or to work around them? Otherwise is there a behaviour specification for this layer visibility or can we handle this ourselve?

Thanks for all help.

Best regards,

Oliver

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10 Replies
OliverBoesche
New Contributor II

We tried that. The problem with this solution is, that the tiles are not aligned correctly. In addition we have tranparent tiles where the difference is bigger between the extents.

Unfortunatly, this is no solution.

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