Ordnance survey to Google earth

[nilesh33]

Hi Freinds,

I have ordnance survey (2D) in CAD format. I am using 'Civil 3D>>Planning & analysis tab' to assign co-odinate system and to import 'Google earth' images into the drawing.

I have assigned 'British National Grid (ORD SURV GB)' co-ordinate system to the Civil 3d drawing and imported Google earth images at some place.

There is difference of around 1-3m between 'Ordnance Surey' & Google image.  How to match these two co-ordinate systems ?

Any help would be appreciated.

Thanks,

Nilesh

[antoniovinci]

You are in the wrong place, sir: this is a Map forum, not a C3D one...

[nilesh33]

Hi antoniovinci,

I know it is Map 3D forum, but my question is related to this forum.

For your info, if you change 'workspace' in civil 3d to 'planning and analysis' then you can use all map 3d commands.

Thanks,

Nilesh

[antoniovinci]

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nilesh33 wrote:

if you change 'workspace' in civil 3d

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Ain't no Civil at all, but I trust you, sir...

[parkr4st]

1-3 meters could be the best you will get trying to line up the photos to the coordinate system.  Do you have any ground based data to measure from?  The CS is presumed to be correct but without any ground based check you can't be absolutley sure.  The photos may not be geo-referenced any closer than 1-3 meters.

Do you want to draw features based on drawing over the photo or is the photo going to be used a a background in the map?  How close to want the photo to align?

dave

[neilyj666]

I'd agree that 1-3 m is probably as good as you'll get with Google earth images. Any better would require a purchased aerial image that is correctly referenced with a decent resolution e.g. 25cm per pixel.