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    AutoCAD Map 3D

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    Active Contributor
    Posts: 46
    Registered: ‎01-30-2009

    Oblique Projection

    484 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
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    Active Contributor
    Posts: 46
    Registered: ‎01-30-2009

    Re: Oblique Projection

    02-03-2010 09:07 AM in reply to: Victoria12
    Can anyone help me, please?
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    Mentor
    Posts: 256
    Registered: ‎10-10-2003

    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
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    Active Contributor
    Posts: 46
    Registered: ‎01-30-2009

    Re: Oblique Projection

    02-03-2010 04:36 PM in reply to: Victoria12
    Thanks, Gordon. I will try that.
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    Active Contributor
    Posts: 46
    Registered: ‎01-30-2009

    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
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    Contributor
    yooper_75
    Posts: 21
    Registered: ‎05-07-2008

    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
    M3D 2012 and 2013
    Win 7 Pro x64
    HP 8200 i7 - 16GB RAM
    AMD Radeon HD 6350
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    Active Contributor
    Posts: 46
    Registered: ‎01-30-2009

    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?
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    Mentor
    Posts: 256
    Registered: ‎10-10-2003

    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
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    Valued Contributor
    rick-chappell
    Posts: 85
    Registered: ‎01-20-2010

    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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