How do I change a projection for a layer which is misregistered (without changing coordinates)?

Occurrence

Vector objects such as Lines, Polylines or Polygons have been digitised into the incorrect projection. In this case, reprojection does not work, as the object coordinates will change (move). For
example the vector object may have been created in the incorrect UTM Zone, or the wrong projection was selected during import and registration of the file.

How can this be modified without recreating the objects/registration?

Solution

For rasters or surface grid images, simply use Table>Raster>Modify Image Registration, and select a new Projection, or edit control points. Note that editing control points may cause errors, which ought to be fixed through rectification.

For points, you can simply delete the map, using Table>Maintenance>Table Structure and un-ticking Table is Mappable, and then re-create the points.


If a Polygon or Polyline table has been saved into the wrong projection the only solution is to export the incorrect MapInfo TAB file as a MID/MIF file using the Table>Export menu option.

Subsequently, change the projection line into the desired projection and re-import the file.

An example is presented below:
 
1. Export the MapInfo TAB file as a MID/MIF file and browse to the MID/MIF files in Windows Explorer.
Open the MIF file into a text editor such as Word Pad or Note Pad.
Observe the line beginning CoordSys Earth Projection.......


 
2. Export a MapInfo table which is saved in the projection you want the original file to be located in.
Open the exported MIF file into a text editor such as Word Pad or Note Pad.
 
3. Highlight the line beginning CoordSys Earth Projection..................... in the correct projection MIF file and copy and
paste this line into the CoordSys Earth Projection line in the incorrect file and save.
 
4. Re-import the altered MID/MIF file using the Table>Import menu option.
 
5. The imported file should now be located correctly.

Would you like to...

Print this page Print this page

Email this page Email this page

Post a comment Post a comment

Subscribe me

Remove Highlighting Remove Highlighting

Edit this article

User Opinions (19 votes)

100% thumbs up 0% thumbs down

How would you rate this article?




Thank you for rating this article.

Related Articles

No related articles were found.

Attachments

No attachments were found.

Last Updated on: 9th of August, 2011