Use of Coordinate Systems in Mobile Mapping context

Orbit has the objective to support coordinate systems as they are described in the EPSG database by the OGP (International Association of Oil and Gas Producers).

Up to now Orbit supports any combination Geographic, Geocentric and Metric projected coordinate systems.
If it is your wish to use Feet projected coordinate system, please let us know. It is on our wishlist for a future update.

More information :

• It is strongly recommended to read first the documentation about Coordinate Reference Systems in Orbit.
• If you would like to know more about coordinate systems go ahead with Coordinate Reference System in Theory.

Orbit supports any combination of mobile mapping data and any coordinate system on import. But be wise :

• The coordinate reference system should be part of the metadata of each resource.
• It is advised that all georeferenced resources are using the same CRS to avoid processing time of continuous coordinate transformation. If required convert CRS on import run.
• When converting the coordinate system of image positions apply the according adjustments on all orientation angles referring the reference direction of the coordinate systems (most probably north).

More information :

• Understand Mobile Mapping data in Orbit
• Manage your Mobile Mapping Runs
• Supported Resources for Mobile Mapping
• Import Mobile Mapping data in Orbit

The coordinate systems of all runs in a project must be the same. Convert CRS on import run if required, see above.

More information :

• Manage your Mobile Mapping Projects

Point X,Y,Z measurements are expressed in the Map coordinate system.

• When using the Orbit desktop products the Map crs can be set from the MapCanavs Statusbar.
  
• When using the Orbit Web client it is the administrator who defines the Map and publication coordinate system.
• If no vertical CRS is set the Z of your mobile mapping data will be retained.

Distance, Length, Area or Volume measurements are expressed in metric units.

• The results are calculated in a local projection centered on the current view position.
  This intelligent technique gives the most accurate metric measure result at all time.
• Projected measure results are always displayed in meters.

More information :

• Measure in Mobile Mapping data

When saving measurements as features to a dataset or inventory theme, measured vertices will be converted to the dataset CRS. Attribute rules using a projected measure result will be saved as calculated, see above.

Remarks :

• A measurement can only be saved to a dataset if the dataset CRS has been defined.
• When saving measurements to a 2D dataset only X and Y will be retained.
• When saving measurements to a 3D dataset and no vertical dataset CRS has been defined the measurement Z will be retained, see above.
• When saving measurements to a 3D dataset with a defined vertical dataset CRS, the measured Z will be converted accordingly.

More information :

• Dataset Structure Contents > Structure > Manage Models in Dataset > Coordinate

Datasets available in the Asset Inventory procedures are named as Themes. A Theme CRS can be set on creation. While importing or exporting a theme, coordinate transformation and or re-projection is possible as well :

• Create New Inventory Theme
• Import Inventory Theme
• Export Inventory Theme

Working with coordinate systems requires special attention. It is easy respecting some simple rules but mistakes are easily made as well.
Tips on doing feature extracting from mobile mapping :

1. Use the same coordinate system for all resources
2. Avoid any intermediate coordinate transformation
3. Extract features in the same coordinate system as the resource mobile mapping data
4. Only convert coordinates on export

If you would have any coordinate system related question, contact the Orbit Support team (support at orbitgt dot com).