Adding XY Data from Excel

[JenniferRamey]

I am new to ArcGIS and have been to the basic courses but I'm not understanding how to get my Excel spreadsheet into my Arcmap. I have created a spreadsheet that has longitude and latitude decimal format that I am wanting to be able to plot on my map.  I can get the data into the map but it does not appear to be plotting correctly.  My X axis is my long and my Y axis is my lat, I have the coordinate system set.  Please help.

[JackWilliamson]

Thank you Caleb; your suggestion worked a treat.

Is it just me, or does this procedure for adding XY data seem a little opaque.  Surely this is something Arc could be revised to work out for itself.  I know, I know .. it's made me a better human to do the projection myself.  But still ...

[DarrenWiens2]

The process is always exactly the same:

1.) Know what coordinate reference system the data in your XY table are in

2.) Display the data, in that CRS (define the CRS)

3.) Project the data to whatever CRS you want

ArcMap can't choose the CRS for you, because there are literally an infinite number of CRSs. The CRSs listed in ArcGIS are just those that happen to have names, but you can make your own custom CRS if you want.

[JackWilliamson]

Yes there are infinitely many CRS, but Arc could query the data frame

where one wants to drop the xy-data. Couldn't it?

[MelitaKennedy]

It currently does that. In the Add XY Data tool in ArcMap, it uses the data frame's coordinate system by default. If you have a basemap loaded first, that often sets the coordinate system to Web Mercator which is usually not what data in a text or Excel or other table is using. A geographic coordinate system is more likely. 

We could start checking the xy table extent versus various coordinate system but for geographic coordinates there's no way to differentiate between NAD83, NAD83 (2011), NAD27, WGS84, ITRF2014, GDA1994, and so on. UTM zones all have the same coordinate system extents so to get a chance at the right zone, the map would already have to be zoomed into that zone.

Melita

[curtvprice]

The default behavior does confuse newbies.  XY data in a table are almost always in GCS, it sure would be great if the wizard defaulted to the GCS part of the data frame CS instead of the whole thing, especially if a check of the first few rows of x and y were within -90-90 and -180-180. A little late to implement this in ArcMap but it would be useful usability thing to add to Pro (haven't tried the workflow there yet.)