Setting the coordinate system

InfoWorks WS Pro has a default coordinate system that is used for all new networks. The coordinates entered for network objects are assumed to relate to this system unless you specify otherwise.

Note: Automatic system allocation does not apply to databases without a map control (map control is set in the Options dialog). If users wish to use web mapping services on such GeoPlans, it is necessary to set an alternative coordinate system.

Tip: You can change the coordinate system as soon as you have created a network, before adding any objects.

To change the coordinate system for an existing network

1. Select GeoPlan Set Coordinate System.
   Note: This option is not available unless a map control has been selected on the GeoPlan page of the Options dialog.
2. Select the coordinate system to be used:
   • For ArcGIS Engine and ArcGIS Desktop map controls, click Browse and select a Projected Coordinate System from the standard Windows File Open dialog.
   • For a MapXtreme map control, InfoWorks WS Pro is supplied with a number of nationally-recognised coordinate systems from which you can select the required system:
     1. Click in the Select Coordinate System dialog to display the Choose Coordinate System dialog.
     2. Select the desired projection system.
        Note: Although the coordinate system list for a MapXtreme map control includes 'Longitude and Latitude' options, these are geographic not projected coordinate systems and therefore should not be selected for use in InfoWorks WS Pro.
     3. Click OK. The Choose Coordinate System dialog closes and the name of the selected coordinate system is displayed in the Projection box.
   • For the ArcGIS Maps map control, there are a number of projected coordinate systems from which you can select the required system:
     1. Click in the Select Coordinate System dialog to display the Choose Coordinate System dialog.
     2. Select the desired projection system.
        Note: The Choose Coordinate System dialog only lists projected coordinate systems that are compatible with the ArcGIS Maps map control.
     3. Click OK. The Choose Coordinate System dialog closes and the name of the selected coordinate system is displayed in the Projection box.
3. If you choose Non-Earth coordinates, enter your projection system bounds. (These fields are greyed out for all other coordinate systems.) The maximum values for X and Y must be greater than the minimum values, and all values must be greater than zero.
4. If you want the selected system to become the default for all new networks, click the Default button and confirm that the coordinate system is to be used in future.
5. Click OK to apply the new coordinate system.

After changing the coordinate system, the coordinate values that have been entered for any existing network objects will remain the same, so the position of these objects on the background map will change to reflect the new system. You may then need to move existing network objects.

Geographic coordinate transformations

When using ArcGIS Desktop/ArcGIS Engine as the map control, geographic transformations can be specified to allow data sets which have different geographic coordinate systems to be mapped together.

Click the geographic coordinate transformations Edit button on the Projected Coordinate System dialog to display the Geographic Transformations dialog.

Transformations available are those which are related to the current GeoPlan coordinate system. One transformation may be selected for each available coordinate system.

Transformations are saved as part of the coordinate system. Changing the GeoPlan coordinate system will clear all previously set transformations.