# Help identifying coordinate system

Discussion created by gissing on Aug 7, 2013
Latest reply on Aug 8, 2013 by curtvprice
Hi all,

I have what I hope is a simple problem from an ArcMap novice.

I have two sets of shapefiles for a country. One set is shapefiles for roads and lakes within the country. The other is one shapefile for the country boundary. The set with country features (shapefiles for roads, lakes, etc) all have defined coordinate systems and overlay just fine on the fly. The country boundary does not have a defined coordinate system and that's where I'm stuck.

The extent values for the country boundary are shown in this picture. From what I've read, I'm guessing the original coordinate system is projected rather than geographic (based on the size of the values).

[ATTACH=CONFIG]26559[/ATTACH]

I read online that one can use some trial and error and keep defining projections until you hit on the original coordinate system but I had no luck with this.

If I'm right in thinking that my steps are (1) define the projection of the country boundary shapefile, and then (2) project it to overlay with the road & lake shapefiles, is there something I'm missing in order to do step 1?

In case it helps, here are the details of the lake and road shapefiles. All the shapefiles (including my problematic one) come from the same office.

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Extents
Top: 756142.379950 m
Right: 1142656.619454 m
Left: 690629.179290 m
Bottom: 74790.443758 m

Projected Coordinate System: Ghana TM
Projection: Transverse_Mercator
False_Easting: 900000.00000000
False_Northing: 50000.00000000
Central_Meridian: -1.00000000
Scale_Factor: 1.00000000
Latitude_Of_Origin: 4.66666667
Linear Unit:  Meter

Geographic Coordinate System: GCS_Clarke_1866
Datum:  D_Clarke_1866
Prime Meridian:  Greenwich
Angular Unit:  Degree

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Top: 769664.186871 dd
Right: 1142674.650690 dd
Bottom: 57841.861131 dd
Left: 650523.913583 dd

Geographic Coordinate System: GCS_WGS_1984
Datum:  D_WGS_1984
Prime Meridian:  Greenwich
Angular Unit:  Degree

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Any help greatly appreciated!