<div dir="ltr"><p>Dear PROJ community,<br>
I am using a GNSS (Emlid REACH RS2 )to collect ground control points for drone mapping
and supporting a project of monitoring vegetation after fire. I have collected data in LAT,LON (CRS EPSG 4326) and ellipsoidal
height (m) and would like to transform it to another CRS. Target
horizontal is EPSG: 25831 and target height is based on EGM2008 (EPSG
3855).</p><p>I just discovered PROJ and I am having issues with the vertical transformation. <br></p><p>Using Linux Ubuntu 11 and installed PROJ using anaconda with:</p><p><conda install -c conda-forge proj></p><p><conda install -c conda-forge proj-data></p><p>I tested with:</p><p><echo -2.69713764 43.37551925 | cs2cs +init=epsg:4326 +to +init=epsg:25830></p><p>which outputs: -2.69713764 43.37551925 which is fine.</p><p>However, I don't understand very well how to perform the vertical grid shift.</p><p>I tried:</p><p>1. <echo -2.69713764 43.37551925 102.635| cs2cs +init=epsg:4326 +vgridshift +to +init=epsg:25830 +grids=egm08_25.gtx></p><p>2.<echo -2.69713764 43.37551925 102.635 | proj +init=epsg:4326 +proj=vgridshift +grids=egm08_25.gtx><br></p><p>But the first try ignores the height and the second got me an error message:</p><p>"can't initialize operations that produce angular output coordinates<br>program abnormally terminated"</p><p>Thank you for your help,</p><p>Inti<br></p><p><br></p><p><br></p><br>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr">
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