topic help needed with WGS84 map in ArcGIS Enterprise Portal Questions https://community.esri.com/t5/arcgis-enterprise-portal-questions/help-needed-with-wgs84-map/m-p/371993#M5057 <HTML><HEAD></HEAD><BODY><SPAN>Hi,</SPAN><BR /><BR /><SPAN>I have a paper map that I am trying to digitize. I have scanned it and am trying to use ArcGIS to export the values and locations of the contour lines, but even before that, I have some trouble understanding the coordinate system used by this map.</SPAN><BR /><BR /><SPAN>On the map, it is stated that "Positions are referred to WGS84 datum" and immediately below that, "Projection: mercator". From my limited understanding of cartography, WGS84 is a geographic coordinate system (GCS), meaning that it is not a projection. So why is there a projection to this map?</SPAN><BR /><BR /><SPAN>Therefore, the next question is, which spatial reference system should I use for this map?</SPAN><BR /><BR /><SPAN>Appreciate any help here.</SPAN><BR /><BR /><SPAN>Thanks.</SPAN></BODY></HTML> Fri, 09 May 2014 06:23:03 GMT BobbyLim 2014-05-09T06:23:03Z help needed with WGS84 map https://community.esri.com/t5/arcgis-enterprise-portal-questions/help-needed-with-wgs84-map/m-p/371993#M5057 <HTML><HEAD></HEAD><BODY><SPAN>Hi,</SPAN><BR /><BR /><SPAN>I have a paper map that I am trying to digitize. I have scanned it and am trying to use ArcGIS to export the values and locations of the contour lines, but even before that, I have some trouble understanding the coordinate system used by this map.</SPAN><BR /><BR /><SPAN>On the map, it is stated that "Positions are referred to WGS84 datum" and immediately below that, "Projection: mercator". From my limited understanding of cartography, WGS84 is a geographic coordinate system (GCS), meaning that it is not a projection. So why is there a projection to this map?</SPAN><BR /><BR /><SPAN>Therefore, the next question is, which spatial reference system should I use for this map?</SPAN><BR /><BR /><SPAN>Appreciate any help here.</SPAN><BR /><BR /><SPAN>Thanks.</SPAN></BODY></HTML> Fri, 09 May 2014 06:23:03 GMT https://community.esri.com/t5/arcgis-enterprise-portal-questions/help-needed-with-wgs84-map/m-p/371993#M5057 BobbyLim 2014-05-09T06:23:03Z Re: help needed with WGS84 map https://community.esri.com/t5/arcgis-enterprise-portal-questions/help-needed-with-wgs84-map/m-p/371994#M5058 <HTML><HEAD></HEAD><BODY><SPAN>Have a look at this</SPAN><BR /><BR /><A href="http://downloads2.esri.com/support/documentation/ao_/710Understanding_Map_Projections.pdf">http://downloads2.esri.com/support/documentation/ao_/710Understanding_Map_Projections.pdf</A></BODY></HTML> Fri, 09 May 2014 11:05:12 GMT https://community.esri.com/t5/arcgis-enterprise-portal-questions/help-needed-with-wgs84-map/m-p/371994#M5058 michaelcollins1 2014-05-09T11:05:12Z