In ArcMap I have a data frame with a base map using the WGS_84_Pseudo_Mercator projection.

When I add a shapefile layer with a WGS_84_Pseudo_Mercator projection, the shapefile position appears slightly off, in respect to the base map - About 200 pixels off.

I've tried defining a new projection, and even reprojecting the shapefile layer, but it always appears in the same position.

Everything seems to be correct, so I have no idea where should I be looking for - I've even tried to load the shapefile in QGIS, and it appears in the correct position.

Any ideas?

  • 1
    roughly how far is 200 pixels? What is the basemap? Do you know that it is accurate?
    – jbalk
    Jun 12, 2017 at 6:43
  • IMO you should avoid using WGS84_Pseudo_Mercator (EPSG:3857) as much as possible. It seems to me this projection is always a bit wonky in its behaviour. Reproject all your data to something more fitting e.g. UTM and apply the right transformation method to ensure spatial correctness of your data. Inprecise alignment of data is often produced by using wrong transformation methods. These methods will also used by 'on the fly'-reprojection.
    – Nightwatch
    Jun 13, 2017 at 7:57
  • Can you check in View-> Data Frame Properties for the data frame coordinate system and see if it matches your file's?
    – NettaB
    Jun 13, 2017 at 9:33

1 Answer 1


I suggest checking the original projections of both the basemap file(s) and the new shapefile. I had a projection issue stemming from an attempt to reproject my data, which caused 0s to inexplicably infiltrate my attribute table. Try adding the basemap and the shapefile without changing their projections from their original formats.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.