What unit of measure is x,y points?

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03-24-2020 10:57 AM
JackBoyd
New Contributor III

In ArcGISOnline, I loaded a file of 159 counties and in the attribute table, created two additional fields, a lat and long.  I added a calculated feature using Geometry($feature).x for the x value and similar for the y.  The data doesn't appear to be degrees or radians.  Am I missing a conversion?  Thanks.  

The lat / long of Appling County, GA is 31.7 deg N, 82.3 deg W. 

The calculation for this county in ArcGIS is x = -9,160,360 and y = 3,730,477.  

See screen shot.  image

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DanPatterson_Retired
MVP Emeritus

meters, it appears to be in a Web Mercator projection

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DanPatterson_Retired
MVP Emeritus

meters, it appears to be in a Web Mercator projection

KenBuja
MVP Esteemed Contributor

These are coordinates in meters using the Web Mercator projection.

JackBoyd
New Contributor III

Thanks for the fast reply.  I was able to find additional help on how to convert the meter data to lat/lon in degrees and add latitude and longitude fields in my attribute table. Lat/Long unit conversion with Arcade 

Since I had to tweak it a little to use in my ArcGISOnline attribute table, I thought i would add some additional instructions:  

I added two additional fields to the attribute table, one for Latitude and one for Longitude.  

Add the latitude field as type 'double,' click 'calculate' and add the arcade script:

var y = Geometry($feature).y
var originShift = 2.0 * PI * 6378137.0 / 2.0;
var lat = (y / originShift) * 180.0;
lat = 180.0 / PI * (2.0 * Atan( Exp( lat * PI / 180.0)) - PI / 2.0);
lat

Add the longitude field of type 'double', click 'calculate' and add the arcade script:

var x = Geometry($feature).x
var originShift = 2.0 * PI * 6378137.0 / 2.0;
var lon = (x / originShift) * 180.0;
lon

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