Global Mapper v26.0

SID file alignment problem V10.02

wncblueridge
wncblueridge Global Mapper UserTrusted User
edited March 2009 in Bug Report
When starting will a UTM nad 83 sid file loaded, I am having problems with loading a NC State Plane sid file in v10.02. The NCSP file comes in about 500 miles to the NE. It appears that the problem is v10.02 does not see that the NCSP file is in feet. It comes up in meters. When I change the projection from feet to meeter it works.

When I use the same procedure in v9.0, the NCSP sid file correctly alligns. It appears that v9.03 loads the NCSP sid file with feet as the unit.

here is a link to the two files in case you need them:

Untitled Document

John

Comments

  • global_mapper
    global_mapper Administrator
    edited March 2009
    John,

    I took a look and it appears that the NCSP .sid file is the problem. It specifies a projection code of 32119, which is North Carolina State Plane/NAD83 with units of meters, not feet (see NAD83 / North Carolina: EPSG Projection -- Spatial Reference or the official EPSG database, both of which confirm this). The .sid file also does not specifically specify a linear unit, so the default of meters for the projection code is used.

    In version of Global Mapper prior to v10.02 this was actually incorrectly encoded and the 32119 projection code resulted in units of feet, but this has since been fixed, which of course causes improperly coded files to not load at the correct location.

    What really needs to happen is that the provider of the NCSP files needs to change the EPSG projection code in their .sid files to 2264, which is the NCSP projection with feet
    units.

    What you can do if you want these files to load correctly and don't anticipate encountering any correctly encoded files in the future is to add the following line to the epsg_codes.txt file in your Global Mapper 10 install folder:

    32119,SPCS,NAD83,feet,ZONE=3200

    This will over-ride the build in definition for EPSG projection code 32119 with the one that the .sid file really should have used.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • wncblueridge
    wncblueridge Global Mapper User Trusted User
    edited March 2009
    Thanks Mike. Once again I'm amazed.
    John

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