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I want to define projection for a Shape file. The projection system is: "NAD_1983_StatePlane_Montana_FIPS_2500" which is referred in Qgis 1.9 as EPSG:102700.

The same projection system is not available in Qgis 1.8. Here it is designated as "NAD 83/Mountana(ft)" and has EPSG:2256 and "NAD83/Mountana" and has EPSG:32100.

My problem is if I want to define projection in Qgis 1.8 what projection system should I use? EPSG:2256 or EPSG:32100?

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    102700 is originally an Esri number. The unit is the US survey foot. EPSG:2256 uses the international foot. These are NOT equivalent (the false easting differs by almost 4 m). EPSG:32100 uses meters.
    – mkennedy
    Commented Sep 25, 2013 at 17:08

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2256 and 32100 are the same except 32100 is in meters. I looked up NAD_1983_StatePlane_Montana_FIPS_2500 and the proj4 is the same as 2256 except that lat1 and lat2 are switched, which I don't believe really matters.

So 32100 should work. Otherwise, create a prj file for the shapefile with the following WKT:

PROJCS["NAD_1983_HARN_StatePlane_Montana_FIPS_2500",GEOGCS["GCS_North_American_1983_HARN",DATUM["NAD83_High_Accuracy_Regional_Network",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic_2SP"],PARAMETER["False_Easting",600000],PARAMETER["False_Northing",0],PARAMETER["Central_Meridian",-109.5],PARAMETER["Standard_Parallel_1",45],PARAMETER["Standard_Parallel_2",49],PARAMETER["Latitude_Of_Origin",44.25],UNIT["Meter",1],AUTHORITY["EPSG","102300"]]

I got this from http://www.spatialreference.org/ which is a great reference for projection problems.

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    I think you have 32100 and 2256 confused on the units. Please double-check in the EPSG registry: epsg-registry.org.
    – mkennedy
    Commented Sep 25, 2013 at 17:11
  • Ah, you're right. My bad. And I was looking right in an epsg file too: <2256> +proj=lcc +lat_1=49 +lat_2=45 +lat_0=44.25 +lon_0=-109.5 +x_0=599999.9999976 +y_0=0 +ellps=GRS80 +datum=NAD83 +to_meter=0.3048 +no_defs no_defs <>
    – Russell at ISC
    Commented Sep 25, 2013 at 19:26
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    MK is right, Arun, use 32100 or the provided prj WKT.
    – Russell at ISC
    Commented Sep 25, 2013 at 19:28

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