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<p class="MsoNormal"><span lang="EN-GB">Hi Jelmer,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Aruba’s CRS is a local TM projection with its central meridian through the Hooiberg. Unfortunately it is not in the EPSG registry.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">An approximate transformation is available in the PCTrans software by the Dutch Hydrographic Service:<o:p></o:p></span></p>
<p class="MsoNormal"><a href="https://english.defensie.nl/topics/hydrography/documents/applications/2018/06/06/pctrans5_20180601"><span lang="EN-GB">https://english.defensie.nl/topics/hydrography/documents/applications/2018/06/06/pctrans5_20180601</span></a><span lang="EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">If you want to use PROJ, the transformation parameters of PCTrans can probably be found in de documentation of the software or obtained by sending a message to NSGI:<o:p></o:p></span></p>
<p class="MsoNormal"><a href="https://www.nsgi.nl/over-ons/nsgi/contact"><span lang="EN-GB">https://www.nsgi.nl/over-ons/nsgi/contact</span></a><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Precise (sub metre) transformation parameters are available at the local authorities DLV, and m</span><span lang="EN-GB">ore precise (centimetre) transformation parameters should be computed for DLV this year. However,
I’m not sure if they share these. Contact information can be found here:</span><span lang="EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><a href="https://www.overheid.aw/home-ned/departementen_46763/item/dienst-landmeetkunde-en-vastgoedregistratie-dlv_4615.html"><span lang="EN-GB">https://www.overheid.aw/home-ned/departementen_46763/item/dienst-landmeetkunde-en-vastgoedregistratie-dlv_4615.html</span></a><span lang="EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">If this contact information is outdated, you can contact NSGI (see above) to ask to get you in touch with DLV.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind regards, Jochem<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:NL">From:</span></b><span lang="EN-US" style="mso-fareast-language:NL"> PROJ <proj-bounces@lists.osgeo.org>
<b>On Behalf Of </b>Jelmer Baas<br>
<b>Sent:</b> vrijdag 7 februari 2020 16:01<br>
<b>To:</b> proj@lists.osgeo.org<br>
<b>Subject:</b> [PROJ] Proper projection system for Aruba<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I’m trying to convert coordinates from what seems to be a custom projection system in Aruba, without much luck.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">In their drawings, they have data around 3000, 18000. Whatever existing projection system I use (EPSG 24819, EPSG 32619), I end up at a completely different location.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">For example:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">echo 2936 18088 | cs2cs +proj=utm +zone=19 +ellps=intl +towgs84=-216.408,279.243,-203.231,-8.56912,40.8756,-12.5593,15.8909 +units=m +to +proj=webmerc +datum=WGS84<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-8178296.58 17850.76 22.52<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">echo 2936 18088 | cs2cs +proj=utm +ellps=intl +towgs84=-216.408,279.243,-203.231,-8.56912,40.8756,-12.5593,15.8909 +units=m +to +proj=webmerc +datum=WGS84<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-830835.88 16729.91 101.08<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">This is way outside the expected area. In 3857, the data should be somewhere between<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-7800000, 1417000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-7777000, 1393000<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I do have the attached “.gtf” files, but I’m unsure how to apply this in proj. Is the above string correct? What am I missing?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Any help would be greatly appreciated.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Jelmer Baas<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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