How To: Reproject shapefiles from the Lambert Conformal Conic to GCS NAD 83 (Decimal Degrees)


This example shows how to use the Projection Utility to reproject shapefiles from the Lambert Conformal Conic Projection to the Geographic Coordinate system.


Example projection parameters

Projection Name: Lambert_Conformal_Conic
Units: Meters
Central Meridian: -85.7639032405
Reference Latitude: 37.8193170574
Standard Parallel 1: 36.9374859125
Standard Parallel 2: 38.7011482024
Geographic Coordinate System: GCS_GRS_1980
False Northing: 0
False Easting: 0

Projection Name: GCS_North_American_1983
Units: Decimal Degrees
Projection: None (Geographic Coordinate System)
Datum: NAD83

  1. Load the shapefile and initialize the Projection Utility.

    A. Start ArcView.
    B. Select File > Extensions.
    C. Check 'Projection Utility Wizard' and click OK.
    D. Create a new view and add the shapefile to be projected.
    E. Select File > ArcView Projection Utility.

    The shapefile should be listed in the 'Step 1' dialog box.
    [O-Image] Projection Utility - Step1 dialog box
    If the Coordinate System in the 'Step 1' dialog box shows 'unknown,' you need to define the input projection parameters as shown below. If the content of that field is other than 'unknown,' you can skip the input projection parameters definition.

  2. Click Next on the 'Step 1' dialog box.
  3. Define the input projection parameters. For our example, use the input parameters shown above.

    A. Make sure the 'Show Advanced Options' box is checked.
    B. Set Coordinate System Type to Projected.
    C. Set the Name dropdown list to Custom.
    D. Set the Units for your projection.
    E. Switch to the Parameter tab.
    F. Set the Base Projection.
    G. Set base projection parameters (Central_Meridian, Central_Parallel, and so forth).
    H. Set the Geographic Coordinate System.
    I. Set False Easting and False Northing.
    J. Set the Prime Meridian.

    [O-Image] Projection Utility - Step 2 dialog box
  4. Click Next on the 'Step 2' dialog box. Click Yes if you are prompted to save the coordinate system.
  5. Click Next on the 'Step 3' dialog box. Click No if you are prompted to specify a Geographic Transformation.

    We are changing from a coordinate system using the GRS80 sphereoid to a coordinate system using the North American Datum 1983 (NAD83). Since NAD83 is based on the GRS80 spheroid, we will not specify a geographic transformation.

  6. Click Browse to specify a name and location for the new shapefile.
  7. Click Next on the 'Step 4' dialog box.
  8. Review the Summary of the projection parameters.
  9. Click Finish.