topic Re: Working on the edge of a of a grid projection. in Civil 3D Customization Forum

Working on the edge of a of a grid projection.

minerdetails — Tue, 03 Dec 2013 02:47:33 GMT

I have a client who is working on the edge of a MGA coordinate zone - as they are near the edge of the zone their scale factor is large and needs to be factored in to all setouts (it makes 50mm of difference over 100 metres.)

their previous solution has been to work day to day at 1 to 1 scale and then xreference this back into a MGA projection by using a scale factor around a single point false origin.

As they are moving away from this false origin - the scale factor is changing slightly.

Is it possible to create a user grid at 1 to 1 for the day to day use and then query this into a MGA drawing. via ADEQUERY to bring it back to MGA ?

Re: Working on the edge of a of a grid projection.

Anonymous — Tue, 03 Dec 2013 04:37:07 GMT

Hi,

This seems to be an AutoCAD Map related question. Could post this to Map 3D Developer forum instead of this [Civil 3D Developer Forum ] ?

Thanks,

Partha

Re: Working on the edge of a of a grid projection.

Anonymous — Tue, 03 Dec 2013 16:05:20 GMT

Two trains of thought apply here depending on size of project. If it is small enough, choose a combined scale factor at the center of the project and use it.

Or compute scale factors at each point if the project is larger than is comfortable. It matters not that they are at the edge of the zone; they need to pick a scale factor and stick with it.

Also, one needs to assess what the change in scale factor is across the job. If it is in the mm range, I probably wouldn't worry about it.