3 Signs You Have The Wrong Coordinate System

3 Signs You Have The Wrong Coordinate System:

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Three Signs You Have The Wrong Coordinate System by Elliott Johns, GIS Specialist, GEO-Jobe GIS Consulting.  What is this article about?
This article explains how to identify that you have the wrong coordinate system in ArcMap and how to correct the coordinate system once it is identified.

1.  ArcMap does not support the file type.

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Answer:  Esri does not support all types of files, but it’s easier to add data to ArcMap by dragging over one file data from ArcCatalog than several different files from Windows.

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Another way to add data to ArcMap is to use the “Add Data” button and simply brows to the folder you need.

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2.  The shapefile is lacking a spatial reference.

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Answer:  In order to change or assign a coordinate system, you need to go to the properties of the shapefile in ArcCatalog.   You can do this by Right-clicking on the shapefile and selecting properties.

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Choose the XY coordinate system tab and hit the “Select” button.

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Select the coordinate system that matches that of the other shapefiles you are currently working with in ArcMap.  Once you have found the correct coordinate system click  ”add,” and then “apply” the coordinate system.

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Now the shapefile can be added back into ArcMap.

3.  The dataframe properties are set to a different coordinate system.

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Answer:  If you have a blank mxd with no data, then the dataframe properties do not have a spatial reference.  However, the first shapefile that you place into ArcMap determines the spatial reference of the mxd. When another shapefile is added to ArcMap that has a different spatial reference, it sometimes cannot be found (well at least not that easily).  In order to locate the new data, you can utilize the “Full Extent” button in ArcMap.

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You can change the spatial reference of the shapefile as we discussed earlier or you can change the spatial reference of the dataframe.   Right-Click on Layers (in the Table of Contents) and choose properties, under the system coordinates tab select “Import.”

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Browse to the location of the shapefile you just added, select it and click “add.”  This will change the spatial reference of the dataframe to match the spatial reference of your shapefile.

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