Reproject Shapefile NAD 27 to NAD 83

[907Trekker]

I have spent way too much time watching Autodesk's videos and reading through the forums today trying to figure this out with no success. According to this link http://docs.autodesk.com/MAP/2010/ENU/AutoCAD%20Map%203D%202010%20User%20Documentation/HTML%20Help/i... I feel that if I assign a coordinate system to my drawing and then import a shapefile that is on a different coordinate system and attach the shapefile to my drawing AutoCAD should reproject it automatically to my drawings coordinate system. But this is not the case. I have a shapefile in NAD27 and a drawing in NAD83 and when I follow these steps the data comes in incorrectly. Is it possible to reproject a shapefile in NAD27 to NAD83 in Civil3d? I must be missing something. Thanks, Mark

[antoniovinci]

1] open a blank drawing

2] _ADESETCRDSYS and set NAD83

3] _MAPIMPORT => browse to the NAD27 shape, then set the entering CRS as NAD27 here:

[907Trekker]

Thanks, that does bring them in correctly.  I brought in the object data and then exported them back out as an SDF file.  Now I can connect to that file.

So I take it there is no way for me to just just connect to data (not import) and have it reproject "on the fly" in Civil 3D?

[Joe-Bouza]

does this work?

[907Trekker]

Unfortunately, no.  I think that is if you have data in a coordinate system but you want to tell CAD to ingore that and assume it is in someting else.  Not really sure why you would use that.

[antoniovinci]

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907Trekker wrote:

just connect to data (not import) and have it reproject "on the fly" in Civil 3D?

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In my old Autocad release, I often use the _MAPTRACKCS command to display other CRS coordinates in realtime: give it a try, sir.

[Murph_Map]

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@907Trekker wrote:

Unfortunately, no.  I think that is if you have data in a coordinate system but you want to tell CAD to ingore that and assume it is in someting else.  Not really sure why you would use that.

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One reason may because map is reading the wrong projection file (.prj). Try to rename the .prj file with your shp file as "opps.prj" then connect and follow Joe's advice. 

[907Trekker]

Yes, I like that command when I'm trying to view LL and working in grid.

[907Trekker]

I renamed the prj file, reconnected to the data and followed Joe's advice with no success. I don't think CAD was having trouble reading the shp file's projection file and I know the data really IS in NAD27. All of this works just fine in ESRI software. Can Civil 3D reproject data from 27 to 83 similar to ESRI when I connect to it, not import it? I'm starting to think it can't. Antoniovinci's idea of importing it worked (MAPIMPORT) but then I had to export it back out (MAPEXPORT) and connect to the new shapefile (MAPCONNECT). Basically reprojecting it on my own. I'm just trying to cut out those first two steps. Per that first link I posted it seems like it should work.

[antoniovinci]

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907Trekker wrote:
Yes, I like that command when I'm trying to view LL and working in grid.

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The powerful MAPTRACKCS allows you to view any other CRS on-the-fly, not only the default Lat/Long: enter its properties, and set NAD83.