<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p><br>
</p>
<div class="moz-cite-prefix">Le 31/05/2023 à 01:24, Javier Jimenez
Shaw a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CADRrdKus03g3Dnawboo8cjztqx1R7NBUiTjMJF8hZsXfYCaaYQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="auto">
<div>Thanks Even for the quick response.
<div dir="auto"><br>
</div>
<div dir="auto">Can I create a CRS as WKT with the ob_tran?</div>
</div>
</div>
</blockquote>
<p>in a PROJ-specific way, yes:</p>
<p>$ bin/projinfo "+proj=ob_tran +o_proj=moll +o_lon_p=40
+o_lat_p=50 +lon_0=60 +type=crs"<br>
PROJ.4 string:<br>
+proj=ob_tran +o_proj=moll +o_lon_p=40 +o_lat_p=50 +lon_0=60
+type=crs<br>
<br>
WKT2:2019 string:<br>
PROJCRS["unknown",<br>
BASEGEOGCRS["unknown",<br>
DATUM["World Geodetic System 1984",<br>
ELLIPSOID["WGS 84",6378137,298.257223563,<br>
LENGTHUNIT["metre",1]],<br>
ID["EPSG",6326]],<br>
PRIMEM["Greenwich",0,<br>
ANGLEUNIT["degree",0.0174532925199433],<br>
ID["EPSG",8901]]],<br>
CONVERSION["unknown",<br>
METHOD["PROJ ob_tran o_proj=moll"],<br>
PARAMETER["o_lon_p",40,<br>
ANGLEUNIT["degree",0.0174532925199433,<br>
ID["EPSG",9122]]],<br>
PARAMETER["o_lat_p",50,<br>
ANGLEUNIT["degree",0.0174532925199433,<br>
ID["EPSG",9122]]],<br>
PARAMETER["lon_0",60,<br>
ANGLEUNIT["degree",0.0174532925199433,<br>
ID["EPSG",9122]]]],<br>
CS[Cartesian,2],<br>
AXIS["(E)",east,<br>
ORDER[1],<br>
LENGTHUNIT["metre",1,<br>
ID["EPSG",9001]]],<br>
AXIS["(N)",north,<br>
ORDER[2],<br>
LENGTHUNIT["metre",1,<br>
ID["EPSG",9001]]],<br>
REMARK["PROJ CRS string: +proj=ob_tran +o_proj=moll
+o_lon_p=40 +o_lat_p=50 +lon_0=60"]]<br>
<br>
</p>
<blockquote type="cite"
cite="mid:CADRrdKus03g3Dnawboo8cjztqx1R7NBUiTjMJF8hZsXfYCaaYQ@mail.gmail.com">
<div dir="auto">
<div><br>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, 31 May 2023, 00:43
Even Rouault, <<a
href="mailto:even.rouault@spatialys.com"
moz-do-not-send="true" class="moz-txt-link-freetext">even.rouault@spatialys.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<p>Javier,</p>
<p>I suspect you might be able to apply the azimuth by
using the infamous +proj=ob_tran. The tricky part
will be to find on which parameter(s) of ob_tran
(o_lat_p, o_lon_p, lon_0) to map it.</p>
<p>Possibly relevant, there's at least 2 different code
implementations attempting at reproducing the Spilhaus
from Esri, which include a azimuth parameter:<br>
</p>
<p>- cf <a
href="https://github.com/OSGeo/PROJ/issues/1851#issuecomment-943138537"
target="_blank" rel="noreferrer"
moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/OSGeo/PROJ/issues/1851#issuecomment-943138537</a></p>
<p>- or <a
href="https://github.com/neocarto/bertin/blob/main/src/projections/spilhaus.js"
target="_blank" rel="noreferrer"
moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/neocarto/bertin/blob/main/src/projections/spilhaus.js</a>
+ <a
href="https://github.com/d3/d3-geo/blob/main/src/rotation.js"
target="_blank" rel="noreferrer"
moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/d3/d3-geo/blob/main/src/rotation.js</a></p>
<p>The maths ressemble those of proj=ob_tran</p>
<p>Even<br>
</p>
<div>Le 31/05/2023 à 00:24, Javier Jimenez Shaw a
écrit :<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Hi</div>
<div><br>
</div>
<div>Some use cases of Esri "local" projection are
arriving to my desk. This projection works in Esri
software, but not in PROJ (obviously also not in
QGIS)<br>
</div>
<br>
<div>One example is this WKT1_ESRI<br>
</div>
<br>
PROJCS["Hycroft001",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Local"],PARAMETER["False_Easting",13264.924],PARAMETER["False_Northing",46473.418],PARAMETER["Scale_Factor",1.00025],PARAMETER["Azimuth",15.786],PARAMETER["Longitude_Of_Center",-116.7048269],PARAMETER["Latitude_Of_Center",42.88212865],UNIT["Foot_US",0.3048006096012192]]<br>
<div>
<div><br>
</div>
<div>Looking at their documentation, it seems to
be this one:<br>
</div>
<div><a
href="https://desktop.arcgis.com/en/arcmap/latest/map/projections/local.htm"
target="_blank" rel="noreferrer"
moz-do-not-send="true"
class="moz-txt-link-freetext">https://desktop.arcgis.com/en/arcmap/latest/map/projections/local.htm</a></div>
<div><br>
</div>
<div>The biggest difference I see with the
Orthographic from PROJ is the Azimut parameter.
I have the impression that the azimut is just a
rotation of the axes, but it is not clear to me
in the Snyder book (page 145. If you do not have
it, it is available at <a
href="https://pubs.er.usgs.gov/publication/pp1395"
target="_blank" rel="noreferrer"
moz-do-not-send="true"
class="moz-txt-link-freetext">https://pubs.er.usgs.gov/publication/pp1395</a>
)</div>
<div><br>
</div>
<div>Is there are alternative in PROJ?</div>
<div>Does it make sense to add this
transformation?</div>
<div><br>
</div>
<div>Thanks<br>
</div>
<div>Javier<br>
</div>
</div>
<div>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div>.___ ._ ..._ .. . ._. .___ .. __ . _. .
__.. ... .... ._ .__</div>
</div>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
<pre>_______________________________________________
PROJ mailing list
<a href="mailto:PROJ@lists.osgeo.org" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">PROJ@lists.osgeo.org</a>
<a href="https://lists.osgeo.org/mailman/listinfo/proj" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">https://lists.osgeo.org/mailman/listinfo/proj</a>
</pre>
</blockquote>
<pre cols="72">--
<a href="http://www.spatialys.com" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
</div>
</blockquote>
</div>
</div>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
</body>
</html>