AutoCAD Map 3D General Discussion

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Active Contributor
Victoria12
Posts: 46
Registered: ‎01-30-2009
Message 1 of 9 (740 Views)

Oblique Projection

740 Views, 8 Replies
02-02-2010 02:10 PM
Hello all,

Is there a way to compensate for an oblique projection?
I am trying to import a shape file with the following: "Nad_1983_Hotline_Oblique_Mercator_Azimuth_Natural_Origin" (for more details see attached file) into a map done on Autodesk Map 3D 2006 with assigned Coordinate System UTMNAD83, Zone 18, US feet. Polygons, of course, are oblique. Is there anything that can be done to remedy the latter?

Thanks a million,

Victoria
Active Contributor
Victoria12
Posts: 46
Registered: ‎01-30-2009
Message 2 of 9 (740 Views)

Re: Oblique Projection

02-03-2010 09:07 AM in reply to: Victoria12
Can anyone help me, please?
Valued Mentor
gluckett
Posts: 374
Registered: ‎10-10-2003
Message 3 of 9 (740 Views)

Re: Oblique Projection

02-03-2010 11:49 AM in reply to: Victoria12
Hi it looks like your PRJ file is not what you expected.

Why not do this:
1. Ditch the PRJ file.
2. Create a new DWG file with the Coordinate System that matches your shp (you may have to create it)
3. Import your SHP into DWG
4. Save your new DWG (and close it)
5. Start a new DWG with the UTM Zone 18
6. Attach your drawing you just created.
7. Query - Location All
8. Detach Source Drawing
9. Save new drawing with UTM 18 coordinate system...

regards
gordon
Active Contributor
Victoria12
Posts: 46
Registered: ‎01-30-2009
Message 4 of 9 (740 Views)

Re: Oblique Projection

02-03-2010 04:36 PM in reply to: Victoria12
Thanks, Gordon. I will try that.
Active Contributor
Victoria12
Posts: 46
Registered: ‎01-30-2009
Message 5 of 9 (740 Views)

Re: Oblique Projection

02-04-2010 04:31 AM in reply to: Victoria12
Unfortunately, it did not work. Does anyone have any other idea I can try?

Thanks a million,

Victoria
Contributor
yooper_75
Posts: 21
Registered: ‎05-07-2008
Message 6 of 9 (740 Views)

Re: Oblique Projection

02-05-2010 02:19 PM in reply to: Victoria12
Where did the above instructions go wrong?

"Michigan_Georef_NAD83_meters" - is this the same as MI83-OB - NAD83 datum, GeoRef Hotline Oblique for whole State (meter)? Edited by: yooper_75 on Feb 5, 2010 5:21 PM
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Active Contributor
Victoria12
Posts: 46
Registered: ‎01-30-2009
Message 7 of 9 (740 Views)

Re: Oblique Projection

02-05-2010 03:23 PM in reply to: Victoria12
They did not go wrong. There is not way to get rid of the projection by using the instructions above. The only way is to reproject using the appropriate software. Do you know of any free one?
Valued Mentor
gluckett
Posts: 374
Registered: ‎10-10-2003
Message 8 of 9 (740 Views)

Re: Oblique Projection

02-05-2010 03:32 PM in reply to: Victoria12
Really, I reproject all my GIS data using AutoCAD Map 3D. I can reproject SHP, SDF, Oracle, Sql Server, DWG, etc.

How about this:

1. Set your current DWG to UTM83-10F
2. Drag and drop your SHP into AutoCAD Map 3D
3. Right-click the SHP file in the Display Manager and save as SDF.
4. You now have a UTM83-10F SDF file you can import into your DWG.

regards
gordon
Valued Contributor
rick-chappell
Posts: 85
Registered: ‎01-20-2010
Message 9 of 9 (740 Views)

Re: Oblique Projection

02-05-2010 03:35 PM in reply to: Victoria12
Victoria12,
Deleting (or even renaming) the PRJ file from the shape will remove the existing projection. Once importing it, the coordinates would be the same as original, except the system wouldn't "know" what coordinates the new drawing is.
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