<div dir="ltr"><div>At the end you and I agree that GeoJSON is in WGS84 (but not the people from d3, based on the comment on the issue). How this data is later projected in the web browser is another story.</div><div>One of the multiple complains about EPSG:3857 "WGS 84 / Pseudo-Mercator" (aka "Web Mercator") is that it uses ellipsoidal coordinates (WGS84), ... and projects them in a sphere. If I am right, EPSG:3395 "WGS 84 / World Mercator" is using an ellipsoid.<br></div><div><br></div><div>I guess that you are trying to convert the coordinates from WGS84 to spherical ones to be "compliant" with the web browser library that you are using. (This is not a GeoJSON problem).</div><div>Unfortunately I do not know the options needed in ogr2ogr.</div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__<br>Entre dos pensamientos racionales <br>hay infinitos pensamientos irracionales.<br><br></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 10 Nov 2022 at 16:38, Gonzo Bard <<a href="mailto:gonzo.bard@gmail.com">gonzo.bard@gmail.com</a>> wrote:<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 dir="ltr"><span style="color:rgb(80,0,80)"><div>> <span style="color:rgb(0,0,0)">Why do you want to convert the points to an sphere? GeoJSON is also defined in WGS84</span></div><div><br></div></span><span style="color:rgb(0,0,0)">GeoJSON data is rendered in the browser using projections:</span><br style="color:rgb(0,0,0)"><span style="color:rgb(0,0,0)">Web Mercator - </span><a href="https://github.com/d3/d3-geo#geoMercator" target="_blank">https://github.com/d3/d3-geo#geoMercator</a><br style="color:rgb(0,0,0)"><span style="color:rgb(0,0,0)">Stereographic North - </span><a href="https://github.com/d3/d3-geo#geoStereographic" target="_blank">https://github.com/d3/d3-geo#geoStereographic</a><br style="color:rgb(0,0,0)"><span style="color:rgb(0,0,0)">According to the developer of the projection engine, it is expected that geographic points transferred to the projection lie on a sphere:</span><br style="color:rgb(0,0,0)"><a href="https://github.com/d3/d3-geo/issues/265#issuecomment-1234323369" target="_blank">https://github.com/d3/d3-geo/issues/265#issuecomment-1234323369</a><br style="color:rgb(0,0,0)"><div style="color:rgb(0,0,0)"><br></div><div style="color:rgb(0,0,0)">On the other hand, the data I want to place on the map is only prepared under the assumption that the planet is a spheroid.<br></div><div style="color:rgb(0,0,0)"><br></div><div style="color:rgb(0,0,0)">Based on NGA research:<br></div><div style="color:rgb(0,0,0)"><a href="https://web.archive.org/web/20141009142830/http://earth-info.nga.mil/GandG/wgs84/web_mercator/(U)%20NGA_SIG_0011_1.0.0_WEBMERC.pdf" target="_blank">https://web.archive.org/web/20141009142830/http://earth-info.nga.mil/GandG/wgs84/web_mercator/(U)%20NGA_SIG_0011_1.0.0_WEBMERC.pdf</a><br></div><div style="color:rgb(0,0,0)">see Figure A1 – Latitude versus Absolute Projection Difference (in kilometers) <br></div><div style="color:rgb(0,0,0)">I came to the conclusion that the users of my application can be significantly misled (up to several tens of kilometers).</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">чт, 10 нояб. 2022 г. в 18:11, Javier Jimenez Shaw <<a href="mailto:j1@jimenezshaw.com" target="_blank">j1@jimenezshaw.com</a>>:<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 dir="ltr">Why do you want to convert the points to an sphere? GeoJSON is also defined in WGS84<br clear="all"><div><div><div dir="ltr">.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__<br>Entre dos pensamientos racionales <br>hay infinitos pensamientos irracionales.<br><br></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 10 Nov 2022 at 11:24, Gonzo Bard <<a href="mailto:gonzo.bard@gmail.com" target="_blank">gonzo.bard@gmail.com</a>> wrote:<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 dir="ltr"><div>Greetings to all!</div><div><br></div>I use Natural Earth data:
<a href="https://www.naturalearthdata.com/downloads/" target="_blank">https://www.naturalearthdata.com/downloads/</a><br>> All Natural Earth data use the Geographic coordinate system (projection), WGS84 datum<br>That is, Natural Earth data are points on an ellipsoid.<br><br>To display geographical data on the map, I pre-convert it from Shapefile to GeoJSON.<br>To do this, I use the ogr2ogr program (GDAL library).<br>In ogr2ogr there are conversion options:<div>from -s_srs <a href="https://gdal.org/programs/ogr2ogr.html#cmdoption-ogr2ogr-s_srs" target="_blank">https://gdal.org/programs/ogr2ogr.html#cmdoption-ogr2ogr-s_srs</a> </div><div>to -t_srs <a href="https://gdal.org/programs/ogr2ogr.html#cmdoption-ogr2ogr-t_srs" target="_blank">https://gdal.org/programs/ogr2ogr.html#cmdoption-ogr2ogr-t_srs</a>.</div><div><br><div>If I understood correctly, the GDAL project uses OSGeo / PROJ as a projection library.<br><br>Please tell me what the values for -s_srs and -t_srs should be in order to perform the conversion:<br>points located on an ellipsoid (WGS84 datum) ===> to points located on a sphere?<br></div></div></div>
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