topic Survey123 - Custom Basemap Offset in ArcGIS Survey123 Questions https://community.esri.com/t5/arcgis-survey123-questions/survey123-custom-basemap-offset/m-p/867357#M27295 <HTML><HEAD></HEAD><BODY><P>Hi all,</P><P></P><P>I'm using a custom TPK basemap in my Survey123 app to collect data.</P><P>However, after I collected about 300 points, I realised that the basemap has an offset of about 10 meters.</P><P></P><P><IMG alt="Custom Basemap" class="image-1 jive-image" height="460" src="https://community.esri.com/legacyfs/online/438578_Capture1.JPG" width="498" /></P><P><IMG alt="" class="image-2 jive-image j-img-original" src="https://community.esri.com/legacyfs/online/438579_Capture2.JPG" /></P><P></P><P>Cheers,</P><P>Marco</P></BODY></HTML> Sun, 03 Mar 2019 22:17:03 GMT MarcoPoetsch_ret 2019-03-03T22:17:03Z Survey123 - Custom Basemap Offset https://community.esri.com/t5/arcgis-survey123-questions/survey123-custom-basemap-offset/m-p/867357#M27295 <HTML><HEAD></HEAD><BODY><P>Hi all,</P><P></P><P>I'm using a custom TPK basemap in my Survey123 app to collect data.</P><P>However, after I collected about 300 points, I realised that the basemap has an offset of about 10 meters.</P><P></P><P><IMG alt="Custom Basemap" class="image-1 jive-image" height="460" src="https://community.esri.com/legacyfs/online/438578_Capture1.JPG" width="498" /></P><P><IMG alt="" class="image-2 jive-image j-img-original" src="https://community.esri.com/legacyfs/online/438579_Capture2.JPG" /></P><P></P><P>Cheers,</P><P>Marco</P></BODY></HTML> Sun, 03 Mar 2019 22:17:03 GMT https://community.esri.com/t5/arcgis-survey123-questions/survey123-custom-basemap-offset/m-p/867357#M27295 MarcoPoetsch_ret 2019-03-03T22:17:03Z Re: Survey123 - Custom Basemap Offset https://community.esri.com/t5/arcgis-survey123-questions/survey123-custom-basemap-offset/m-p/867358#M27296 <HTML><HEAD></HEAD><BODY><P>To what coordinate system&nbsp;was your base map generated?</P><P></P><P>What coordinate system are you using for the data in Survey 123?</P><P></P><P>Are differences generally in the same direction and distance for all points?</P><P></P><P>Coordinate systems&nbsp;need to match or you will have a tranformation&nbsp;error.&nbsp; These errors are typically in the same direction and distance.</P><P></P><P>Are you manually placing the point locations or using the internal GPS of a device?&nbsp; Many GPS units in mobile devises can have substantial errors dependent upon time of day and satellite positions.&nbsp; These errors will typically be more random in direction and distance.&nbsp; I have seen 10-15 m errors from iDevices.</P></BODY></HTML> Sun, 03 Mar 2019 22:59:50 GMT https://community.esri.com/t5/arcgis-survey123-questions/survey123-custom-basemap-offset/m-p/867358#M27296 LanceCole 2019-03-03T22:59:50Z