1

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?

  • 2
    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 Sep 25 '13 at 17:08
2

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.

  • 1
    I think you have 32100 and 2256 confused on the units. Please double-check in the EPSG registry: epsg-registry.org. – mkennedy Sep 25 '13 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 Sep 25 '13 at 19:26
  • 1
    MK is right, Arun, use 32100 or the provided prj WKT. – Russell at ISC Sep 25 '13 at 19:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.