topic Re: DEM generation on ortho mapping arcgis pro using GCPs in ArcGIS Pro Questions https://community.esri.com/t5/arcgis-pro-questions/dem-generation-on-ortho-mapping-arcgis-pro-using/m-p/178649#M7932 <HTML><HEAD></HEAD><BODY><P>Hi Napoleon,</P><P></P><P>What GPS did you use to obtain the z values of your GCPs?&nbsp;If you used a normal GPS (not a differential GPS), your elevation data might be off by a magnitude of 30m or more. Also, what imagery are you using (drone, satellite)?</P><P>To produce a DTM in ArcGIS you need to provide your own DTM.&nbsp; If you done have one, ArcGIS provides you with their elevation data.</P><P>Did you try and produce your DEM while leaving your GCP elevation data as "unknown" and compare with the results you have?&nbsp;</P><P></P><P>Regards,</P><P></P><P>Jurie</P></BODY></HTML> Sun, 01 Sep 2019 09:09:11 GMT JurieTheron1 2019-09-01T09:09:11Z DEM generation on ortho mapping arcgis pro using GCPs https://community.esri.com/t5/arcgis-pro-questions/dem-generation-on-ortho-mapping-arcgis-pro-using/m-p/178648#M7931 <HTML><HEAD></HEAD><BODY><P>Hi all,</P><P>I am having problems to get accurate elevation data from a DEM generated in ortho mapping. I am using GCPs, and the elevation data values in the DEM are way different than the GCPs. I followed all the steps in the official documentation and I can not identify the problem. Any of you guys had the same problem? Please help!&nbsp;</P><P>Thanks,</P><P>Napoleon</P></BODY></HTML> Mon, 05 Aug 2019 23:45:34 GMT https://community.esri.com/t5/arcgis-pro-questions/dem-generation-on-ortho-mapping-arcgis-pro-using/m-p/178648#M7931 NapoleonGudino-Elizondo 2019-08-05T23:45:34Z Re: DEM generation on ortho mapping arcgis pro using GCPs https://community.esri.com/t5/arcgis-pro-questions/dem-generation-on-ortho-mapping-arcgis-pro-using/m-p/178649#M7932 <HTML><HEAD></HEAD><BODY><P>Hi Napoleon,</P><P></P><P>What GPS did you use to obtain the z values of your GCPs?&nbsp;If you used a normal GPS (not a differential GPS), your elevation data might be off by a magnitude of 30m or more. Also, what imagery are you using (drone, satellite)?</P><P>To produce a DTM in ArcGIS you need to provide your own DTM.&nbsp; If you done have one, ArcGIS provides you with their elevation data.</P><P>Did you try and produce your DEM while leaving your GCP elevation data as "unknown" and compare with the results you have?&nbsp;</P><P></P><P>Regards,</P><P></P><P>Jurie</P></BODY></HTML> Sun, 01 Sep 2019 09:09:11 GMT https://community.esri.com/t5/arcgis-pro-questions/dem-generation-on-ortho-mapping-arcgis-pro-using/m-p/178649#M7932 JurieTheron1 2019-09-01T09:09:11Z