https://community.esri.com/t5/arcmap-questions/gcs-warning-doesn-t-go-away/m-p/1012800#M1783 <P>Despite all of the layers and my data frame being projected using the same coordinate systems:</P><P>(Projected Coordinate System: NAD_1927_StatePlane_California_I_FIPS_0401<BR />Projection: Lambert_Conformal_Conic<BR />Geographic Coordinate System: GCS_North_American_1927)</P><P>I am still get the warning "This coordinate system has a geographic coordinate system that differs from one or more data sources in the map" when I view the Coordinate System tab in the Properties for the Data Frame. I have pressed the Transformation button and set the proper Transformation (although nothing happens when I press ok).&nbsp;</P><P>If all of the layers and the data frame are in the same coordinate systems, why do I continually get this error message?&nbsp;</P> Wed, 30 Dec 2020 01:43:03 GMT NorthcoastRegional 2020-12-30T01:43:03Z https://community.esri.com/t5/arcmap-questions/gcs-warning-doesn-t-go-away/m-p/1012800#M1783 <P>Despite all of the layers and my data frame being projected using the same coordinate systems:</P><P>(Projected Coordinate System: NAD_1927_StatePlane_California_I_FIPS_0401<BR />Projection: Lambert_Conformal_Conic<BR />Geographic Coordinate System: GCS_North_American_1927)</P><P>I am still get the warning "This coordinate system has a geographic coordinate system that differs from one or more data sources in the map" when I view the Coordinate System tab in the Properties for the Data Frame. I have pressed the Transformation button and set the proper Transformation (although nothing happens when I press ok).&nbsp;</P><P>If all of the layers and the data frame are in the same coordinate systems, why do I continually get this error message?&nbsp;</P> Wed, 30 Dec 2020 01:43:03 GMT https://community.esri.com/t5/arcmap-questions/gcs-warning-doesn-t-go-away/m-p/1012800#M1783 NorthcoastRegional 2020-12-30T01:43:03Z https://community.esri.com/t5/arcmap-questions/gcs-warning-doesn-t-go-away/m-p/1012814#M1785 <P>It usually happens when one of the files has an incorrectly defined coordinate system and projecting it makes it worse.&nbsp; You will have to examine the numeric values of the extents of each layer and not rely on what you see on screen.</P> Wed, 30 Dec 2020 03:21:31 GMT https://community.esri.com/t5/arcmap-questions/gcs-warning-doesn-t-go-away/m-p/1012814#M1785 DanPatterson 2020-12-30T03:21:31Z