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I am trying to reproject a michigan state land shapefile which is the NAD83/ Michigan Oblique Mercator EPSG:3078 to the WPG84 EPSG:4326 projection. However when i try to do this my map gets squished down. I have tried the commands in "Reprojecting from MGRm to WGS84 using open-source tools" with no luck. I need to get these coordinates into a decimal degrees format. Thanks

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Is it still recognizably Michigan? Lat/lon data is displayed as plate carree-like. That will look squashed north-south compared to many other projections including oblique Mercator. –  mkennedy Jan 14 '12 at 23:44

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up vote 4 down vote accepted

Ever since I posted in "Reprojecting from MGRm to WGS84 using open-source tools" last year, I've discovered that none of the EPSG definitions that supposedly describe Michigan GeoRef work correctly. I suspect that it is a flaw in the GDAL/OGR tools, and this has been discussed repeatedly in the GDAL developers forum, but no fix has been made. This is especially problematical for open source users in Malaysia, where a rectified skew orthomorphic (RSO) projection system is used country-wide. (Michigan GeoRef is an instance of an RSO projection, as far as I understand.)

I've also discovered that using uDIG to reproject from GeoRef to whatever seems to work, but I can't figure out why. I'm under the impression that uDIG also uses the GDAL/OGR libraries for conversion, but I may be wrong. I've been meaning to send the uDIG developers a query on that, but haven't gotten around to it yet.

Anyway, take a look at a tutorial I developed for our local N. Michigan township users using uDIG to convert GeoRef to MI State Plane. You can follow the same procedure and see if it works for you in converting to WGS84. (Please let me know if it does.) The tutorial is at: http://www.townshipgis.com/resources/problems-and-workarounds/converting-michigan-georef-to-state-plane-using-open-source-tools

Cheers!

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Thank you!! I have been trying to figure this out for a while now but none of the tools I had tried could do it. I followed your tutorial and it worked perfectly. It was very thorough and easy to follow. I will stop back and up vote your answer when I have enough rep. Thanks again! –  jgelderloos Jan 16 '12 at 23:42
    
I'm glad it worked! I've been wondering if the method was applicable for anything other than State Plane. I don't have enough rep for upvoting anybody, either! <grin> –  Howard Y Jan 21 '12 at 15:48
    
I investigated a bit and found that cs2cs does the transformation correct, but ogr2ogr (and Qgis) does not. I opened a ticket for that: trac.osgeo.org/gdal/ticket/4910. –  Andre Joost Nov 29 '12 at 16:59

Reproject on the fly:

  • add your shape
  • check in the properties if is really in EPSG:3078
  • Open the project properties and set the project CRS to EPSG 4326 and enable the checkbox "enable on the fly CRS transformation"

Create a copy of a vector in a different CRS:

  • add your shape
  • check in the properties if is really in EPSG:3078
  • Click the right mouse button over the vector in the TOC and select "save as...", then make the necessary choices in particular "CRS" that you must set to EPSG 4326
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I have tried both of the above methods several times and these do not work. As Howard pointed out there is a problem with converting from the MiGeoref format that skews or squishes the output. However I should say this is the way to convert between projections in most cases. –  jgelderloos Jan 16 '12 at 23:40
    
I cant edit my previous comment for some reason but I did a quick compare to converting the data with ArcGis. It is slightly different but not until the 6th decimal place(using decimal degrees). I cant see any visible different when overlaying on google maps. –  jgelderloos Jan 17 '12 at 0:21

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