User Defined Coordinate System - V8i

Not sure if I understood you completely, but apparently you're trying to create a custom coordinate system and want to reproject a reference file based on the new one. I can add some v8i tools functionalities to your knowledge base and you can see if they help:

• Right-click in the lower right status field and select Running Coordinates to track the coordinate readout

• In the status bar where the running coordinates are located, LEFT-click and select ACS Position to start displaying latitude and longitude units.
• You can change the rotation angle in the auxiliary coordinates tool settings dialog.
• To reproject a reference file, during attachment- make sure you've selected the orientation "Geographic- Reprojected".

Thankyou for your response,

 I have turned on the acs and can now read long lats from the Active Coordinate System in Long Lats.

Our project area is an Island about 7km long and 2km wide it is orientated when looking from true north on EPSG:28356 pointing towards the north-east, I would like to show it horizontal (for historical engineering grid purposes), previously we have been able to attach a refrence file then move rotate and scale it to bring it into position crude way of handling the re-projection...

Perhaps it would be easier if I can show you two DGNs with some control points, I have attached two DGNs one showing the MGA Coordinate System, the other is the rotated scaled and moved crude version.

If it is possible to re-create an actual coordinate system to best mimic this operation please do tell.

One way to define an engineering coordinate system within MicroStaton is by creating a Rectangular Auxiliairy Coordinate System and setting it active in the desired views. This allows to see the ACS coordinates or enter coordinates using this engineering coordinates. It is possible to modify the view properties so that the view direction is in the same dorection as your engineering coordinates by simply applying a rotation to the view or views.

Of course this use of the ACS means that your "main" coordinates will still remain in the Geographic Coordinates System UTM Zone 56 on GDA94. I understand that you would like to have your main coordinates directly expressed using your engineering coordinate system. The use of a custom Oblique Mercator is an ingenous way to do it. Although this method will introduce a slight deformation in the coordinates the error introduced will be very very small (negligible I belive) on the area of your application. I did try to define such an Oblique Mercator using your data, but since MicroStation offers many different variations of Oblique Mercator and the meaning of each various defining parameters is complex I did not have great results. I did succeed with one variation to obtain an approximative result but not directly but by iteration. I will try in to understand why this does not work with most/all variations of the Oblique Mercator and the exact meaning of the parameters.

In the meantime as an alternative,  it appears you could use the Google Earth integration functionality to obtain an appropriate result. MicroStation offers the ability to compute a Geographic Coordinate Systems based upon the "Azimuthal Equal Area" projection method starting from a set of Google Earth placemarks (from a .kmz file) and equivalent placemarks associated within MicroStation using the "Define Placemark Monument" tool in the Geographic toolbar. I used, to define these placemarks within Microstation, the file FIG-For BE.dgn you provided to obtain the target coordinates expressed in your enginnering coordinates then defined 3 placemarks associated with three Google Earth placemarks I had previously defined in Google Earth. I was satisfied with the result and the ease of use. You should try to obtain the same result using more precise coordinates you may have for your placemarks and tell us if this method is satisfactory.

Alain,

Thankyou very much for taking the time to look over my data. For historic purposes I would like to use the FIG engineering grid to display our project, defining an Oblique Mercator seemed like the logical way of obtaining this result, however my knowledge in this field is limited and I do not understand the parameters required, If you require any further data / information please contact me and I will do everything possible to supply it to you in order to get a result.

I was unaware of the google earth functionality as far as coordinate systems go (my work blocks most google earth applications!). I will play around with this to see if I can obtain an intermediate result.

Thanks again and looking forward to further information.