[Mapserver-users] GPS data Projection

[Changqing Zhou]

HI, I would greatly appreaciate your help on a projection question:

How do I display gps data in lat-long point format on top of the following
MNDOT base road shapefile? How to project the GPS data to the road map system?

(http://www.dot.state.mn.us/tda/basemap/metadata/Roads.htm)

Horizontal Coordinate Scheme  UTM
Ellipsoid  GRS80
Horizontal Datum  NAD83
Horizontal Units  Meters

Below is my simplified maplefile. Note I do not use any projections:

MAP
  NAME           Hennepin County
  IMAGETYPE      png
  #EXTENT         201621.496941 -294488.285333 1425518.020722
498254.511514 # LAEA
  EXTENT		439000 4960000 487000 5010000 #from arcview
  #EXTENT         -97.5 41.619778 -82.122902 49.38562 # Geographic
  SIZE           800 600
  SHAPEPATH      "data"
  SYMBOLSET      "symbols/symbols35.sym"
  FONTSET        "fonts/fonts.list"

  WEB
    TEMPLATE  'hennepinRoads.html'
    IMAGEPATH '/ApacheGroup/Apache2/htdocs/tmp/'
    IMAGEURL  '/tmp/'
  END

  PROJECTION
  # This is Lambert Azimuthal Equal-Area projection for the
  # Continental U.S.
  #  "proj=laea"
  #  "ellps=clrk66"
  #  "lat_0=45"
  #  "lon_0=-100"
  #
  # Alternatively, you can specify an EPSG code.
  # This is the EPSG code for
  # Lambert Azimuthal Equal-Area projection for the U.S.
  #"init=epsg:2163"
  #
  END

LAYER # Hennepin Road layer begins here
  NAME         hennepin_line
  DATA         hennepinm
  STATUS       DEFAULT
  TYPE         LINE

#  PROJECTION
#    "init=epsg:4326"
#  END

  CLASSITEM "Code"
  CLASS
      EXPRESSION '01'
      COLOR 0 0 255
  END
  CLASS
      EXPRESSION '02'
      COLOR 0 0 255
  END
  CLASS
      EXPRESSION '03'
      COLOR 255 0 0
  END
  CLASS
      EXPRESSION '04'
      COLOR 0 255 255
  END

END # Hennepin Roads layer ends here


  # End of LAYER DEFINITIONS -------------------------------

END # end of map file


Thanks,

Changqing