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Creating a Local Projection - ArcMap V10.2

Question asked by timdunlevie on Oct 29, 2014
Latest reply on Oct 30, 2014 by timdunlevie

Hi all,

 

I'm sure this has been asked before....

 

I have grid parameters of a local projection (Mine grid) based on the Map Grid of Australia:

 

Grid Name : Local Grid

Central Scale Factor 1.000000

Origin Local Grid Easting 800,400.025

Origin Local Grid Northing 300,500

Origin MGA Zone 50 Easting (GDA94) 700,000.498m

Origin MGA Zone 50 Northing (GDA94) 6,900,600.233m

Orientation at Origin 31o24’43”MGA

 

Now to add a new grid these are the steps I am using:

1. Data Frame Properties

2. Coordinate system tab

3. New Projected coordinate system

4. Change Projection name from Transverse Mercator to "Local"

5. Enter the above parameters into the "Values" area, where:

False Easting = Origin Local Grid Easting 800,400.025

False Northing = Origin Local Grid Northing 300,500

Scale Factor = 1.0000000

Azimuth = Orientation at Origin 31o24’43”MGA, but I put in decimal degrees of 31.411944

Longitude of center = Origin MGA Zone 50 Easting (GDA94) 700,000.498m - converted to Geographic coords and to decimal degrees (GDA94)

Latitude of center = Origin MGA Zone 50 Northing (GDA94) 6,900,600.233m - converted to Geographic coords and to decimal degrees (GDA94)

 

Unit = meter

Meters per unit = 1

 

Geographic Coordinate system = I changed this to the MGA Zone 50 (GDA94) grid...which the local grid is based on.

 

I don't seem to get real accurate results.

The points are a fair way off where they should be.

 

Have I done everything correct ?

 

Thanks,

Tim

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