LOD - How calculate resolution?

[FabianoScardua]

How can I calculate the resolution (Resolution in map units of each pixel in a tile for each level.) of LOD?

I need setting the LODs for the map manually of my  custom Tiled, but I don't know how calculate this value.

http://resources.arcgis.com/en/help/flex-api/apiref/index.html

Thank's for help

[IvanBespalov]

Tiled map service has all needed information - via this property tileInfo you can access this information in flex

Tile Info:
[INDENT]Height: 512
Width: 512
DPI: 96
[INDENT]Levels of Detail: (# Levels: 16)
Level ID: 0 [Start Tile, End Tile]
Resolution: 0,3515625
Scale: 147748799,285417
Level ID: 1 [Start Tile, End Tile]
Resolution: 0,17578125
Scale: 73874399,6427087[/INDENT][/INDENT]
...

Additional info:
find paragraph "Map Scale and Resolution:"
Mathematical relationships...

[EstherColero]

Hello Fabiano,

Another easy way is create a cache map service in ArcGIS Server (only the service, images are optional) with your own scales and check the rest API (like Ivan hint) or the file c:\arcgisserver\arcgiscache\<serviceName>\Layers\conf.xml.

<LODInfo xsi:type="typens:LODInfo">
    <LevelID>0</LevelID>
    <Scale>500000000</Scale>
    <Resolution>1.1897305029151397</Resolution>
</LODInfo>

Hope it helps 🙂

Regards
Esther

[FabianoScardua]

Thanks for responding.

Ok, but I'm creating the tiles from tilemil (tiles in sqlite) to a mobile application.

The tiles generated by tilemil not have this information.

I will use this tile in the application offline.

[IvanBespalov]

WebTiledLayer sample

Description:
    This sample demonstrates how to add various third-party (tiled|cached)
    map services to your ArcGIS API for Flex application using the WebTiledLayer class
...

Sample of extending TiledMapServiceLayer

[FabianoScardua]

Thanks for the reply.

I've managed to extend the class and load the tiles from a local database (sqlite). The problem is precisely the method buildTileInfo.
How can I get the values �??�??of the resolution if what you have is only png images of each tile? How to calculate this value?

I can load the tiles however they are with some error in the projection which I believe is because of the LOD.

[EstherColero]

I've managed to extend the class and load the tiles from a local database (sqlite). The problem is precisely the method buildTileInfo.
How can I get the values �??�??of the resolution if what you have is only png images of each tile? How to calculate this value?

I can load the tiles however they are with some error in the projection which I believe is because of the LOD.

Hi again,

I do not know how to do that, but if your application always works with the same spatial reference and LODs you can precalculate these values creating a map service with these scales in ArcGIS Server.

If you do not have one, tell me your spatial reference and LODs to help you.

Regards
Esther

[YannCabon]

Hi,

The resolutions of the tiles generated through Tilemill are the same as OpenStreetMap or the tile services served via arcgis.com

See the tiling scheme of the Light Gray Canvas.
http://services.arcgisonline.com/ArcGIS/rest/services/Canvas/World_Light_Gray_Base/MapServer

The resolution of the next level is the half of the current one.