Same Map tiles for different zoom levels.

4 posts, 0 answers
  1. Vidyadhar
    Vidyadhar avatar
    23 posts
    Member since:
    Oct 2011

    Posted 24 Jan 2013 Link to this post

    Hi,

    I have a requirement in my application where I have to use only certain zoom levels of the RadMap, levels 5 through 10. And am using a custom Map Provider inherited from TiledProvider class. I use a set of tiles extracted only for zoom levels 5 through 7. I want to know if I zoom in to a level greater than 7, will the Provider use the same tiles intended for zoom level 7. If not, is there a way I could use the zoom 7 tiles for higher zoom levels.

    Thanks,
    Vidyadhar.
  2. Andrey
    Admin
    Andrey avatar
    1681 posts

    Posted 25 Jan 2013 Link to this post

    Hi Vidyadhar,

    It depends on the implementation of your custom map provider. In the most common case provider will show images from level 7 on level 8 if there are not tiles for level 8. But image will be blurred, because tiles will be expanded.

    Kind regards,
    Andrey Murzov
    the Telerik team

    Explore the entire Telerik portfolio by downloading Telerik DevCraft Ultimate.

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  4. Vidyadhar
    Vidyadhar avatar
    23 posts
    Member since:
    Oct 2011

    Posted 25 Jan 2013 Link to this post

    Andrey,

    Thanks for the reply.
    So does it mean, if the Provider doesn't find the tiles for a particular zoom level, it looks up for the tiles for zoom level below that. Is it recursive. I mean, say I've tiles for just zoom levels 5 through 7 and if I zoom in to level 9, then it would look for tiles for zoom 8 and if it doesn't find any tiles for zoom 8, would it look for tiles for zoom 7 and so on? I observe that my application is crashing when I load it at zoom levels 9 and 10. So wanted to get clarified about this?

    I think my Map Provider is the most common way of building it. Here's the link of the process I followed to create my Map Provider, as suggested by Telerik, http://www.telerik.com/help/silverlight/radmap-howto-custom-provider.html. I customized the GetTile method to meet our needs. I calculate the quadkeys for the tiles using the Microsoft's Tile System,http://msdn.microsoft.com/en-us/library/bb259689.aspx. Once I get the quadkey I look for the corresponding file from the source directory and return the Uri for that tile.


    Thanks,
    Viddy.
  5. Andrey
    Admin
    Andrey avatar
    1681 posts

    Posted 29 Jan 2013 Link to this post

    Hi Vidyadhar,

    No, it doesn't. Map provider always look for the tiles for the particular zoom level. The tiles visualization engine works as reverse pyramid. When you zoom from level 7 (where you have tiles) to the level 8 (where you have not tiles) provider will look for the tiles for level 8. But since there are not tiles for level 8 you will see tiles from level 7.  

    Greetings,
    Andrey Murzov
    the Telerik team

    Explore the entire Telerik portfolio by downloading Telerik DevCraft Ultimate.

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