<div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div>Hi there! Thanks, everyone for your help and recommendations provided.</div><div><br></div><div><br></div><div><br></div><div>Even, I wasn't aware of that, as many other things I see. I thought that It could be translated directly<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><span><blockquote type="cite">
<div dir="ltr">
<p dir="auto">
Genoa 1942 height (Italy)<br>
</p>
<div dir="auto">
<pre>$ <span>echo</span> <span><span>"</span>14.995 37.755 3357<span>"</span></span> <span>|</span> PROJ_NETWORK=ON gdaltransform --debug on -s_srs <span><span>"</span>EPSG:4326+3855<span>"</span></span> -t_srs <span><span>"</span>EPSG:32632+5214<span>"</span></span>
<span>>></span> 1028333.73796622 4195591.29690422 3357</pre>
</div>
</div>
</blockquote></span>
In that situation, "projinfo -t EPSG:32632+5214 -s EPSG:4326+3855
--spatial-test intersects" shows a potential transformation, but
that requires that you need to get (buy) the geo_igm_mar06.grd grid
which does the "ETRS89 to Genoa 1942 height" transformation from
<a href="https://www.igmi.org/en" target="_blank">https://www.igmi.org/en</a> and convert it into a format understood by
PROJ</div></blockquote><div><br></div><div>Prefixing your command with "PROJ_NETWORK=ON" outputs a WTK without the warnings about the missing grid. Should this be enough? </div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><span>
<blockquote type="cite">
<div dir="ltr">
<p dir="auto">EVRF2007 (Estonia)<br>
</p>
<div dir="auto">
<pre>$ <span>echo</span> <span><span>"</span>27.059167 57.714444 318<span>"</span></span> <span>|</span> PROJ_NETWORK=ON gdaltransform --debug on -s_srs <span><span>"</span>EPSG:4326+<span>3855"</span></span> -t_srs <span><span>"</span>EPSG:3301+5621<span>"</span></span>
<span>>></span> 682284.606829111 6401087.4159131 318
</pre>
</div>
</div>
</blockquote>
</span><p>There's only one known transformation between EVRF2007 and ETRS89
or WGS84, but it is for Slovakia.</p></div></blockquote><div>Could you tell me which one it is? I will need to transform Slovakia as well</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Basically, one needs to pick a worldwide height system and then<br>
transform data from multiple regions into it. This is hard because</div></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>[....] <br></div></blockquote><div><br></div><div>Greg, that is exactly what I'm doing but I was not aware of how hard it could be. I would like to have the final dataset in 4326+3855. Would be easier to use the EGM96 instead?<br></div><div><br></div><div>Could you please clarify one thing for me? <br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div> - It is often hard to find transformations from national height datums<br>
to WGS84 Orthometric Height. In the US, I don't know of any. But<br>
there are published geoid models from NAVD88 to NAD83 HAE, and then<br>
one can transform to WGS84(G2159) HAE, and then use EGM2008 to get<br>
WGS84 Orthometric Height.</div></blockquote><div><br></div><div>Converting for example the USA NED 10M dataset, I can't reproject all dataset to 4326+3855 without any intermediary transformation step? For instance, in the below command, isn't the Z output value precise?<br></div><div><span style="font-family:monospace">$ echo "-112.55260 33.48142 643" | PROJ_NETWORK=ON gdaltransform <span style="font-family:monospace">-s_srs "EPSG:6318+5703"</span> -t_srs EPSG:4326+3855<br></span></div><div><span style="font-family:monospace">>> -112.5526 33.48142 643.369641951764</span></div><div><span style="font-family:monospace"><br></span></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>From what others have said, I suspect that there is no *meaningful*<br>
way to have better elevation resolution over such a large area than the <br>
Copernicus data.</div></blockquote><div><br></div><div><span>Andrew, I'm using Copernicus as a fallback when I can't find a dataset with better resolution. Because I need to get the most accurately possible elevation data, I'm merging datasets with 10M, 5M, or 2M pixel resolution with Copernicus data. I'm aware that this is not an easy task, but currently, my main issue is to understand the particularities of transforming the original dataset projection into the desired one. Because my background is not related to GIS makes this task more challenging :'-)<br></span></div><div><span><br></span></div><div><span>Best regards,</span></div><div><span>Diogo<br></span></div><div><br></div><br></div>
</div></div>