<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">I have a CSV with X, Y coordinates and height (Z). These heights are ellipsoid heights and I want them corrected to orthometric height, preferably using EGM2008. I try the following with ogr2ogr, <br class=""><div class=""><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">ogr2ogr -f CSV photon_2018-10-23_t387_1593614567696_EGM2008.csv photon_2018-10-23_t387_1593614567696_EGM2008.vrt -s_srs EPSG:4979 -t_srs EPSG:4326+3855</span></div></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><span style="font-family: Helvetica; font-size: 12px;" class="">passing it a vrt file:</span><div style="font-family: Helvetica; font-size: 12px;" class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px;" class=""><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""><OGRVRTDataSource></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""> <OGRVRTLayer name="photon_2018-10-23_t387_1593614567696"></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""> <SrcDataSource>photon_2018-10-23_t387_1593614567696.csv</SrcDataSource></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""> <GeometryType>wkbPoint</GeometryType></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""> <GeometryField encoding="PointFromColumns" x="X" y="Y" z="Z"/></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""> </OGRVRTLayer></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""></OGRVRTDataSource></div><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo;" class=""><br class=""></div></div></span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><span style="font-size: 11px;" class=""><span style="font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">However the output file, '</span>photon_2018-10-23_t387_1593614567696_EGM2008.csv</span>’ </span>is the same as the input CSV and the vertical values are not corrected. If I loop over each set of coordinates and try gdaltransform, I get the correct result although this is not an efficient process:</div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><div style="margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Menlo; color: rgb(39, 42, 216);" class=""><span style="color: #000000" class=""> cmd = </span>'echo '<span style="color: #000000" class=""> + </span>'"'<span style="color: #000000" class=""> + str(X[i]) + </span>' '<span style="color: #000000" class=""> + str(Y[i]) + </span>' '<span style="color: #000000" class=""> + str(Z[i]) + </span>'"'<span style="color: #000000" class=""> + </span>' | gdaltransform -s_srs "+proj=longlat +datum=WGS84 +no_def" -t_srs "+proj=longlat +datum=WGS84 +no_defs +geoidgrids=egm08_25.gtx"'</div></div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class="">Is there a reason why ogr2ogr is not converting the data?</div><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><br class=""></div></div></body></html>