<div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 21 Mar 2023, 8:06 pm Bo Victor Thomsen via QGIS-User, <<a href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<p>Hi list -</p>
<p>I have a problem with transforming a csv file containing x,y <i>and
</i>z values from EPSG:4326 to EPSG:7416, i.e I want to transform
the height value from LongLat/ WGS84 ellipsoid height to
UTM32/Etrs89 with vertical reference DVR90. <br>
</p>
<p>The file look like this:</p>
<p><font face="monospace"><b>== data.csv, EPSG:4326 id: col1, x:
col3, y: col2, z: col4 ==</b><b><br>
</b>a;55.0;12.0;42.0<br>
b;55.05;12.0;43.0<br>
c;55.10;12.0;44.0<br>
d;55.15;12.0;45.0<br>
e;55.20;12.0;46.0</font><br>
<b>=======================</b></p>
<p><b>Step 1</b>: I import the file into QGIS using the Data Source
Manager --> "Delimited Text" and define the projection to be
EPSG:4326 <i>and</i> to include z values. This works and the
points are shown on my map where I expect them to be (Somewhere in
the middle of Zealand, Denmark)<br>
</p>
<p><b>Step 2</b>: I export the layer as a geojson file using
"Export" --> "Save features as.." from the layer manager and
choose EPSG:7416 (UTM32/ETRS89 with DVR90 as vertical reference.
And to include z-values<br>
</p>
<p>The resulting file looks like this: <br>
</p>
<p><font face="monospace"><b>== data.geojson, EPSG:7416 ==</b><b><br>
</b>{<br>
"type": "FeatureCollection",<br>
"name": "data",<br>
"crs": { "type": "name", "properties": { "name":
"urn:ogc:def:crs:EPSG::4979" } },<br>
"features": [<br>
{ "type": "Feature", "properties": { "field_1": "a", "field_2":
55.0, "field_3": 12.0, "field_4": 42.0 }, "geometry": { "type":
"Point", "coordinates": [ 12.0, 55.0, 42.0 ] } },<br>
{ "type": "Feature", "properties": { "field_1": "b", "field_2":
55.05, "field_3": 12.0, "field_4": 43.0 }, "geometry": { "type":
"Point", "coordinates": [ 12.0, 55.05, 43.0 ] } },<br>
{ "type": "Feature", "properties": { "field_1": "c", "field_2":
55.1, "field_3": 12.0, "field_4": 44.0 }, "geometry": { "type":
"Point", "coordinates": [ 12.0, 55.1, 44.0 ] } },<br>
{ "type": "Feature", "properties": { "field_1": "d", "field_2":
55.15, "field_3": 12.0, "field_4": 45.0 }, "geometry": { "type":
"Point", "coordinates": [ 12.0, 55.15, 45.0 ] } },<br>
{ "type": "Feature", "properties": { "field_1": "e", "field_2":
55.2, "field_3": 12.0, "field_4": 46.0 }, "geometry": { "type":
"Point", "coordinates": [ 12.0, 55.2, 46.0 ] } }<br>
]<br>
}<br>
</font><b>=======================</b></p>
<p>The new file is shown in my map exactly on top of the original
point layer, meaning the horizontal projection is accurate.
However, my z coordinates are not reprojected to the new vertical
reference. All the z-values are exactly the same as the values in
the .csv - file.<br>
</p>
<p>After some digging through Google and other places, I discover
that EPSG:4326 <i>doesn't</i> have a z component. Surprise ! You
have to use EPSG:4979, which is the same as EPSG:4326 with
ellipsoid height. <br>
</p>
<p>But, <i>after </i>repeating <b>step 1</b>, <i>but</i> using
EPSG:4979 as CRS during import, and subsequently repeating <b>step
2</b>, I get the exact same result: No transformation of height
values. <br>
</p>
<p>So, what is not working ? Am I doing something wrong ?? Or is
QGIS incapable of transforming z values ???<br></p></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">The second -- qgis currently doesn't handle vertical crs at all. My recommendation is to use gdal utilities to do a transform respecting vertical datums.</div><div dir="auto"><br></div><div dir="auto">Nyall</div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><p>
</p>
<p><br>
</p>
<pre cols="72">--
Med venlig hilsen / Best regards
Bo Victor Thomsen</pre>
</div>
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