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I am trying to get the coordinates of the coastline. I have made a shapefile with points selected along the coastline, the coordinate system I have the shapefile under is WGS 1984 UTM Zone 30N. I have used the Add XY Coordinates function to get the coordinates of all the points. However the coordinates don't seem to be WGS 1984, I have no idea what they are and the function has no options other than the input shapefile. Does anyone know what units the coordinates are in and how I could get them from the output that I have?

EDIT: An example of the output may help:

Point_X     Point_Y
338,682.05  5,746,608.28
338,708.81  5,746,569.18
338,750.66  5,746,540.37
338,800.49  5,746,530.92
338,839.75  5,746,543.88
338,864.39  5,746,576.43
338,891.86  5,746,620.66
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A UTM projection uses eastings and northings with units of metres, which look like the ones you have shown. To get Latitude and Longitude, you need to reproject it.

In the ArcToolbox:

  • Data Management Tools > Projections and Transformations > Feature > Project

And for the Output Coordinate System, choose:

  • Geographic Coordinate Systems > World > WGS 1984
  • The strange thing seems to be that even in meters the values don't seem to match. From Add XY coordinates I get the above output but if I measure the points then the values seem to be of the order: -591,387.52, 6,774,797.67. Also, when I am using the project function the attribute table collapses to a single point, again with the same type of value as in the OP. – deiniol Jun 28 '15 at 21:34
  • WGS 84 describes a datum (earth's shape), WGS 84 UTM Zone 30N is a UTM projection with a WGS 84 datum. Your X value is the UTM easting and the Y the UTM northing. You need to use the Define Projection tool to establish its existing coordinate reference system PRIOR to using the Project tool to get it to a GCS WGS 84 datum (aka unprojected data in decimal degrees with a WGS 84 datum) – user681 Jun 28 '15 at 22:12
  • @deiniol your data frame possibly has a different coordinate system, such as Spherical Mercator. This is easy to check in ArcGIS. – Mike T Jun 29 '15 at 6:21
  • Hi both thanks for your help, I decided to give up with using the basemap as the reference for my coastline as, as suggested above, it is in WGS84 Web Mercator and after projecting the shapefiles the coordinates would remain in this coordinate system rather than UTM. What I did instead was to georeference a satellite ima – deiniol Jun 29 '15 at 13:06
  • Thanks for your help both. I have given up with using the basemap as it is in WGS84 Web Mercator and I was unable to project the xy coordinates into UTM. What I have done instead is to georeference an image from google earth and use this as the outline of the coastline (gis.yohman.com/up206a/how-tos/…). I georeferenced using geo > WGS84 and the coordinates of the points are in the same coordinate system so I am happy. – deiniol Jun 29 '15 at 13:10

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