How to convert XY to lat/long?

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08-16-2010 09:51 AM
robmundt
New Contributor
We've got a leaf pickup truck that is collecting points on it's routes, and we'd like to plot them. The report returns a table with lat/long coordinates. I've created a shapefile from those using the XY tool, and then set the projection of it to NAD 83 for NC. When I add it to Arcmap along with some of our other data, they're not anywhere close to each other. What is it I'm doing wrong? I attached the original .xls file. Thanks in advance for any help.
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RobertBerger
New Contributor III
Greetings,

if your input points are lat/long then they are probably in WGS 1984. You will have to reproject your data to NAD83 for your data to line up.
Try setting your shape file spatial reference to WGS 1984 (Geographic Coordinate Systems > World) and then add to ArcMap, letting ArcMap do the reprojection on the fly. Does your data line up now?

To reproject: set your projection to WGS 1984 first and then use the projection toolset to reproject your data.

Robert
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WilliamClark
New Contributor II
When I plot your coordinates with the GCS defined as WGS 84, they come out near each other and in a travel pattern as you describe - kind of in west of southern central NC.

Perhaps you didn't define the GCS as you imported the XY data?  Judging by your lat/longs, it appears you should define your GCS as WGS 84 (or whatever your GPS was in).  Projecting into NAD83 would be a separate step after you export your data out of the XY event layer.
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robmundt
New Contributor
That worked like a charm guys. I had set my initial shapefile to NAD 83. When I set it to WGS 84 it popped right where it should. Learned something today, so that's a good thing. Thanks a bunch!
Rob
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