I am trying to add a projection for a shapefile with no GCS or Proj. I used Define Projection (I picked GCS_North_American_1983_CSRS) first, followed by Project (NAD_!983_CSRS_UTM_Zone20N). This matches my other shapefiles projections and data frame as

[ReginaldLawrence]

I am trying to add a projection for a shapefile with no GCS or Proj.  I used Define Projection (I picked GCS_North_American_1983_CSRS) first, followed by Project (NAD_1983_CSRS_UTM_Zone_20N).  This matches my other shapefiles projections and data frame as well.  My result shapefile is nowhere near the rest of my data.  Could I be missing something very simple here?

[DanPatterson_Retired]

when you defined it was it indeed a geographic coordinate system?  ie were the coordinates in longitude (-180 to + 180 degrees) and latitude (-90 to +90 degrees)  

You can assess the coordinates by putting the file into an empty dataframe (ie no basemap, no other data... wiggle the mouse on screen and look).  If they aren't in the range expected, then it wasn't a geographic coordinate system.

Other issues... depending on how the file was created (ie an event layer via add xy as layer file) some people switch longitude and latitude... longitude is the X and latitude is the Y

If the data definitely weren't geographic, it was probably projected, and you would need to define it with the correct projection, which may... or may not, be the projection you want.

[ReginaldLawrence]

It is unknown units when I first add it to the data frame.  I was told it needs to be in NAD 83.

[ReginaldLawrence]

Dan thanks for the quick feedback.  Got into the office this morning and discovered the file was corrupt!

[DanPatterson_Retired]

NAD 83 is a datum, not a coordinate system.  you can have a geographic coordinate system with a nad83 datum, and you can have projected coordinate systems that have a nad83 datum... it is the coordinate system (aka, decimal degrees or meters/feet) that is the key.  It the coordinates fall with the range expected for longitude/latitude then you have a geographic coordinate system with a NAD83 datum.  If not, then it is a projected coordinate system with a nad83 datum.. Unfortunately, there are loads of projected coordinate systems with that datum.

[MelitaKennedy]

I see "St. Croix" in the data's path. Is this the Caribbean island or some other St. Croix. What I'm really asking is--what location does this data represent? With that information, we may be able to narrow down the possible projected coordinate reference systems.

Melita

[ReginaldLawrence]

Already been solved as stated above!  Corrupt shapefile.  Thanks though!