topic Converting from ellipsoidal to arithometric heights (egsa 87) in Data Management Questions https://community.esri.com/t5/data-management-questions/converting-from-ellipsoidal-to-arithometric/m-p/16050#M814 <HTML><HEAD></HEAD><BODY><P><SPAN style="color: #373e4d; font-family: helvetica, arial, sans-serif; font-size: 12px; background-color: #e0edff;">I try to conver from ellipsoidal to orthometric heights with arithmetic function. In input raster 2 i put WGS84.img from \peodata\geoid folder.The results are not right. And now i have the question. The input raster 2 is always the same or it is depended on coordinate system? my files which i want to convert are EGSA87/TM87. What i must put in raster 2=N to convert from ellipsoidal to orthometric in EGSA87?</SPAN></P></BODY></HTML> Mon, 04 Apr 2016 17:25:36 GMT BarbaraBerna 2016-04-04T17:25:36Z Converting from ellipsoidal to arithometric heights (egsa 87) https://community.esri.com/t5/data-management-questions/converting-from-ellipsoidal-to-arithometric/m-p/16050#M814 <HTML><HEAD></HEAD><BODY><P><SPAN style="color: #373e4d; font-family: helvetica, arial, sans-serif; font-size: 12px; background-color: #e0edff;">I try to conver from ellipsoidal to orthometric heights with arithmetic function. In input raster 2 i put WGS84.img from \peodata\geoid folder.The results are not right. And now i have the question. The input raster 2 is always the same or it is depended on coordinate system? my files which i want to convert are EGSA87/TM87. What i must put in raster 2=N to convert from ellipsoidal to orthometric in EGSA87?</SPAN></P></BODY></HTML> Mon, 04 Apr 2016 17:25:36 GMT https://community.esri.com/t5/data-management-questions/converting-from-ellipsoidal-to-arithometric/m-p/16050#M814 BarbaraBerna 2016-04-04T17:25:36Z Re: Converting from ellipsoidal to arithometric heights (egsa 87) https://community.esri.com/t5/data-management-questions/converting-from-ellipsoidal-to-arithometric/m-p/16051#M815 <HTML><HEAD></HEAD><BODY><P>Did the height value change at all?</P><P></P><P>I do not work with rasters very often. I think you may need to put one into the other's coordinate system, including applying the geographic/datum transformation, GGRS_1987_To_WGS_1984_1. Even if the software is converting one raster to the other coordinate system internally (on-the-fly) before doing the calculation, the datum transformation may not be done, which would throw off the results.</P><P></P><P>Melita</P></BODY></HTML> Mon, 04 Apr 2016 21:10:06 GMT https://community.esri.com/t5/data-management-questions/converting-from-ellipsoidal-to-arithometric/m-p/16051#M815 MelitaKennedy 2016-04-04T21:10:06Z