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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 Tile Sets.

The tiling engine support different formats that can each drive the tiling engine, and may have specific configurations.

Formats

Generic

The following fields can be used in MapURL :

  • <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

Format=OpenStreetMap
MapUrl=http://tile.openstreetmap.org
Levels=19

BingMaps

Required extra configuration settings :

Format=BingMaps
ApiKey=<api-key>
ImagerySet=<imagerySet>

WMTS

Format=WMTS
MapUrl=https://geodata.nationaalgeoregister.nl/tiles/service/wmts
Layer=omtrekgerichtevisualisatie
PreferredCRS=28992

WMS

Format=WMS
MapUrl=https://service.pdok.nl/kadaster/au/wms/v2_0
Layer=AU.AdministrativeUnit
CRS=28992

Transparency

When an alpha channel is available (for example PNG images), it can be used on rendering.

UseAlphaChannel=true

When no alpha channel is available, a color and margin can be configured that defines a color that will then be made transparent.

UseTransparentColor=true
TransparentColor=255.255.255
TransparentColorMargin=10

Authentication

You can add username and password to OTM configurations when needed.
Username and password will be sent on every tile request using the HTTP Basic Authentication scheme (using the Authorization header).

Username=xxx
Password=yyy

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 3857.
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
.otm creation.

Format=WMTS
MapUrl=https://geodata.nationaalgeoregister.nl/tiles/service/wmts
Layer=brtachtergrondkaart
PreferredCRS=28992
TransparentColor=255.255.255
UserName=
Password=

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
 
Last modified:: 2025/12/16 09:08