Importing Excel dataset issues

[BonnieEarleywine]

I'm having issues adding a table from Excel into a species occurrences map. It needs a little processing work done so I've exported the data as a shapefile, projected it and set it in the correct coordinate system, but it still appears in a different hemisphere. The format for lat and long columns are "numbers" in Excel, but there must be some other discrepancy or compatibility problem. Any ideas?

[IanMurray]

Make sure that if it supposed to be in southern or western hemispheres you have negative lat or long values.

[BonnieEarleywine]

It has the correct + or - coordinate designations

[IanMurray]

I assumed so, but its been a day of silly mistakes so I thought I'd check.

What method did you use for making the shapfile from points?  Easiest way is usually going to the catalog opening the excel sheet, right clicking on it and selecting "Create Feature Class"

[BonnieEarleywine]

I did not do it that way initially, but I tried it that way after reading your response. It still shows up the same way

[IanMurray]

If you give the shapefile a projection when it comes in, then it could be off since the values you are giving it are raw lat/long values.  I'd try bringing in the points with either an unknown projection or WGS 1984 Geographic Coordinate System. 

Also what projection is your data frame in?

[BonnieEarleywine]

Projection = NAD83 UTM 15N

[IanMurray]

Make sure when you make your feature class to NOT give it a projection, or put it in a Geographic Coordinate System.   Let it just project as a raw lat/long value and it should be fine, as ArcGIS projects all data on the fly to the projection of the dataframe.  Since the data is not projected, it does not need to be given a projection. 

I'm guessing the lat/long values came from a GPS or something?

I made some points for around Memphis, TN from raw lat/long and when I brought them in with in NAD83 UTM 15N it put them off the coast of the Galapagos Islands.

[BonnieEarleywine]

I really appreciate your suggestions. I think the problem arises from the Excel to ArcGIS automatic conversion? The way it was described to me is that ArcGIS is converting the Excel spreadsheet as it brings it into the program although the data is already in the units (decimal degrees) it needs to be in for my map. Is there a way to prevent this?

[markdenil]

If the coordinates are in lat and long,
and you are having coordinate problems with it,
The first step is to cut the whole utm part out.

Bring in the data defined as wgs84 lat long
and compare it to a wgs84 data set of world countries or whatever.
You might even export it again out of ArcMap with the data frame (lat long) coordinates
just to make sure you have it set right in the shp or feature class.

Another check you can make at this stage is to use ADD_XY (for points)
and compare the POINT_X and POINT_Y values to the ones in the excel fields.

Only then should you try any coordinate manipulation, either on the fly with the data frame
or by explicitly projecting the data.

This is all a bit elaborate, but that's what troubleshooting is about.