Global Mapper v25.0

custom stereographic projection

laughlin
laughlin Global Mapper UserTrusted User
edited March 2011 in Projection Questions
browsing the Qs re: custom projections and not sure if the same routine discussed is the ticket for what i'm trying to work with. Want to bring in some geotiff ortho coverage which is in a custom stereographic projection for my study area.

Here are the specs provided with files:
"PEI double stereographic" ref'd to NAD83(CSRS) & GRS80 ellipsoid
Origin: Lat: N 47° 15'; Long: W 63° 00'
Scale factor at origin: 0.999912
False Origin: N 800,000; E 400,000

I have also been provided with detailed specs on the NAD83 (CSRS) datum if needed. Appreciate a quick pointer on setting up the projection if different from general procedures.

thanks!

Comments

  • global_mapper
    global_mapper Administrator
    edited October 2007
    The PEI Double Stereographic projection is represented by the Oblique Stereographic projection in Global Mapper with the parameters that you specified. I have attached a PRJ file for this projection that you can just load on any projection dialog (note you'll need to change the file extension from .txt to .prj).

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Nicole
    Nicole Global Mapper User
    edited June 2010
    I need to explain to my clients how to adjust the prj file to create custom projections. What exactly are the various parameters/numbers in a *.prj file? Some I know but most I am unsure of. Below is an example prj file (reordered). Thanks.

    PROJCS["Transverse_Mercator",
    GEOGCS["Geographic Coordinate System",
    DATUM["D_ETRS_1989",
    SPHEROID["GRS 1980",6378137,298.2572220960423]],
    PRIMEM["Greenwich",0],
    UNIT["degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["scale_factor",1],
    PARAMETER["central_meridian",0],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["Meter",1]]
  • global_mapper
    global_mapper Administrator
    edited June 2010
    There is a detailed description of the WKT PRJ format at http://geoapi.sourceforge.net/2.0/javadoc/org/opengis/referencing/doc-files/WKT.html that you can refer to. Also see spatialreference.org for a huge collection of sample PRJ files for various common projection systems.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • willygest11
    willygest11 Global Mapper User
    edited March 2011
    laughlin wrote: »
    browsing the Qs re: custom projections and not sure if the same routine discussed is the ticket for what i'm trying to work with. Want to bring in some geotiff ortho coverage which is in a custom stereographic projection for my study area.

    Here are the specs provided with files:
    "PEI double stereographic" ref'd to NAD83(CSRS) & GRS80 ellipsoid
    Origin: Lat: N 47° 15'; Long: W 63° 00'
    Scale factor at origin: 0.999912
    False Origin: N 800,000; E 400,000

    I have also been provided with detailed specs on the NAD83 (CSRS) datum if needed. Appreciate a quick pointer on setting up the projection if different from general procedures.

    thanks!

    ok, great job