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Author Topic: MN county coordinates.  (Read 2576 times)

BryanBaker

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MN county coordinates.
« on: November 01, 2016, 10:30:22 AM »
Hello,

The U.S. State of Minnesota has coordinate projections for each of it's counties in the state.  When I try to load them, Agisoft says the coordinate system is not supported.  It is probably a formatting error.  Here is the particular MN projection file that I am trying to use.

PROJCS["NAD_1983_HARN_Adj_MN_Renville_Feet",GEOGCS["GCS_NAD_1983_HARN_Adj_MN_Renville",DATUM["D_NAD_1983_HARN_Adj_MN_Renville",SPHEROID["S_GRS_1980_Adj_MN_Renville",6378414.369,298.2572221008827]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",100000.0],PARAMETER["Central_Meridian",-94.63333333333334],PARAMETER["Standard_Parallel_1",44.53333333333333],PARAMETER["Standard_Parallel_2",44.91666666666666],PARAMETER["Latitude_Of_Origin",44.45611111111111],UNIT["Foot_US",0.3048006096012192]]

Is it possible to either convert this to the proper format or provide an example of how it is formatted?

Regards,
Bryan

KellyNess

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Re: MN county coordinates.
« Reply #1 on: March 09, 2017, 07:12:12 PM »
Bryan,

Not sure if you are still working on this ~4 months later. The way I have been working around this is to use the "settings" option under the reference tab.  In that dialog you can select the .prj file, you would like to use, and it will update your coordinates in your drawing.  It will attempt to update the position of your WGS84 positions in your model view, which is very distorted. 

From here, import your control, select the corresponding GCPs in your photos and "update" and "optimize".

It would be great if we could use the "convert" option for MNCCS .prj files, but I am struggling on how to define the TOWGS84 portion of the .prj file.  Not sure it's even possible...

Kelly Ness

mkrech

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Re: MN county coordinates.
« Reply #2 on: December 21, 2017, 07:55:30 PM »
Wondering if either of you have had any luck with this.

Alexey Pasumansky

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Re: MN county coordinates.
« Reply #3 on: December 22, 2017, 10:01:35 PM »
Hello mkrech,

In the version 1.4.0 after loading or selecting the coordinate system in the Reference pane settings dialog you can also select or specify the Datum transformation settings.

According to the information that I have found (correct me, if I'm wrong) the transformation parameters between NAD83(HARN) and WGS84 can be set as zeros. So if you are customizing PRJ file manually, you can just put TOWGS84 section to the Datum section:
Code: [Select]
DATUM["NAD83 (High Accuracy Reference Network)",
SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],
TOWGS84[0,0,0,0,0,0,0],
AUTHORITY["EPSG","6152"]]
Best regards,
Alexey Pasumansky,
Agisoft LLC