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Orbit Tile Map Service file
An Orbit Tile Map Service resource connection file (*.otm) is a file reference to a Tile Map Service.
It is strongly advised to read first the documentation about Web Based Resources.
Structure
The Orbit Tile Map Service driver relies on a tile engine, a computer graphics technique which generates a larger graphic from re-using a number of smaller graphics to minimize data traffic and increase real-time rendering performance.
Tiled maps are composed of a set of scale-appropriate cartographic renderings, each divided up into regularly spaced image tiles, called Tilesets.
Generic
Custom configuration settings :
- <TileX> : The tile column index.
- <TileY> : The tile row index.
- <Level> : The zoom level (0 means top-level).
- <TileXi> : The tile column index inversed.
- <TileYi> : The tile row index inversed.
Format=Generic MapUrl=http://tile.openstreetmap.org/<Level>/<TileX>/<TileY>.png Levels=19
OpenStreetMap
Default configuration settings OpenStreetMap :
Format=OpenStreetMap MapUrl=http://tile.openstreetmap.org Levels=19
Reasons to use
A Web Service reference file simplifies use of Web resources and enables additional configurations :
- Manage and share web resource in the same way as regular, file based resources.
- Associate an Orbit Legend file.
- Set additional service configurations, see Structure.
Create
Create and edit the .otm file using a simple text editor (e.g. Notepad). Take care of spelling and file syntax.
Legend and Georeference
The resource can be accompanied by an Orbit Legend File and Orbit Resource Descriptor.
A Tile Map Service is most likely georeferenced. The resource coordinate system must be defined via the associated .ord file, just like other regular file based resources.
The CRS for OpenStreetMap is “WGS 84 / World Mercator” EPSG 3395.
If the tile service is using another coordinate system, you can define custom georeference transformation for the top tile, using a .geo file.
Examples
Esri World Imagery
https://services.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer
esri_world_imagery.zip
Format=Generic MapUrl=https://services.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/tile/<Level>/<TileY>/<TileX>.jpg Levels=23 DiskCacheName=services.arcgisonline.com.World_Imagery
PDOK BRT Achtergrondkaart
https://www.pdok.nl
pdok.zip
Format=Generic MapUrl=http://geodata.nationaalgeoregister.nl/tiles/service/tms/1.0.0/brtachtergrondkaart/<Level>/<TileX>/<TileYi>.png Levels=15 TileSize=256 DiskCacheName=geodata.nationaalgeoregister.nl.brtachtergrondkaart
OpenStreetmap
http://www.openstreetmap.org
openstreetmap.zip
Format=OpenStreetMap MapUrl=http://a.tile.openstreetmap.org http://b.tile.openstreetmap.org http://c.tile.openstreetmap.org Levels=19 DiskCacheName=openstreetmap