UTM Zone projection - shapefile

[MattC]

I have obtained some parcel data for Hennepin County, Minnesota, USA
in shapefile format. The .prj file indicates it is UTM Zone 15N.
However, If I choose "Use projection in source file" when opening the
shapefile, I find the area of the data projected more than twice as
large as it should be, and also at the equator. Here is the entirety
of the .prj file associated with the shapefile:


PROJCS["NAD_1983_UTM_Zone_15N",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",
6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",
0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",
500000.0],PARAMETER["False_Northing",
0.0],PARAMETER["Central_Meridian",-93.0],PARAMETER["Scale_Factor",
0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]


I'm not the best at projections and coordinate systems as I don't deal
with too much variation in my data, but I do understand the difference
between the two and how they work for the most part. What is the
difference between UTM zone 15 and 15N? What would be the best way to
correctly display this data in MapInfo, as it appears there is not a
projection option for zone 15N? I have tried opening the shapefile
using both the projection in the source file, and manually choosing
UTM NAD83 > UTM Zone 15. I have also tried the Universal Translator
tool with the "use projection in source file" option and manually
selecting the projection, both with the same results as opening the
shapefile. Interestingly enough, if I select one of the Minnesota
state plane projections (1983, feet), the data appears to match the
outline expected, but too far to the west, so I was wondering if there
is a mix-up in units somewhere. This data was sent to me from a
client who supposedly obtained it from a Minnesota state GIS entity,
so I'm still waiting to hear back from either to see if they can offer
any additional help, but I thought I would try here in the meantime.
I found this site which defines the projections used by Minnesota GIS
agencies, but no mention of "Zone 15N" is made:

http://www.dot.state.mn.us/surveying/ToolsTech/mapproj.html



Thanks,

Matt

[college.atlas]

Matt,

All looks good to me. UTM zones can be defined North and South hence N and S and they're all the same in terms of the basic elements.

Datum, Central Meridian, Origin, False Origin, Scale Factor, Units.

I often avoid using the PRJ file. There were some problems with some PRJ files and versions of MI not parsing the PRJ correctly.

You have used the correct terms for opening the file in Mapinfo if you define the projection yourself.

However I just notice Hennipin is a Lambert Conformal Conic projection not a UTM projection.

http://www.dot.state.mn.us/surveying/ToolsTech/MnCoordSys.pdf 

Try Lamberts as a projection. See how you go. There's a couple under "North American Coordinate Systems"

[Kannan Krish]

As atlas rightly said, its a wrong practice to use .prj file, parsing is creating a bit of issue in most of the nonnative file format in MI.

Using manual method to assign projection is advisable as we are do the same on such conversion process.

 

Hope that helps.

 

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[MattC]

Thanks for the help, good to know that best practice is not to use
the .prj file when working with shapefiles. As I mentioned before, I
don't know the lineage of the data sent to me and it has no metadata
so rather than jam a square peg into a round hole, I'm going to
contact the state agency myself to get the latest data.