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Transparent Tiles

Jun 12, 2013 at 7:16 AM
Edited Jun 12, 2013 at 7:17 AM
I have a few issues when working with transparent tiles, like clouds or other weather tiles.

I have for instance tried the following Open Weather Map.
tileLayer = new TileLayer
   SourceName = "Weather",
   Description = "OSM",
   TileSource = new TileSource("{z}/{x}/{y}.png")

<map:TileLayer SourceName="OpenWeatherMap" Description="© Sample OpenWeatherMap"
This will show all lower zoom levels, hence making it a very blurry image.
When zoomed in you see a dozen layers of clouds.

Setting 'LoadLowerZoomLevels' makes the cloud level go off and on when zooming,
which is not desired behaviour either.

Besides going off and on, when 'LoadLowerZoomLevels' is off, you see tiny white lines between tiles in Silverlight (and black lines between tiles in WinRT). Form some reason the WPF control does not have any lines between the tiles (perhaps this is caused by float/double? rounding).
Jun 12, 2013 at 8:07 AM
You would usually use a transparent tile layer as an overlay above another map tile layer, exactly as done with the "Seamarks" layer in the sample application.

If only the highest zoom level layer is shown, you will of course observe the previous layer switching off and the next layer switching on whenever the highest level changes during zooming. If you have an idea how to avoid this, i'd be glad to here about.

For the tile border rounding errors in Silverlight and WinRT, I can't reproduce them. Do you observe this in one of the standard tile layers like OpenStreetMap?
Jun 12, 2013 at 8:25 AM
Edited Jun 12, 2013 at 11:24 AM

Here is a screenshot of the Silverlight.Web app, using LoadLowerZoomLevels = false.
Since there is no other data behind, you see the white lines.

Jun 13, 2013 at 3:28 PM
Screenshot? Where is it?
Jun 13, 2013 at 6:40 PM
Sorry, I replied by email and the image got lost. It seems I can't insert an image in the webinterface either


Op donderdag 13 juni 2013 schreef ClemensF ([email removed]) het volgende:

From: ClemensF

Screenshot? Where is it?

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