<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Aptos;}
@font-face
{font-family:"times roman";
panose-1:0 0 0 0 0 0 0 0 0 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Thanks Trent, that does help. We default to the triaxial ellipsoid in our definitions and I’ll ask our astrodynamics team how they’d like to proceed.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Hare, Trent M <thare@usgs.gov> <br>
<b>Sent:</b> Monday, December 23, 2024 3:23 PM<br>
<b>To:</b> Reynolds, Scott <scott@agi.com><br>
<b>Cc:</b> Newcomb, Doug <doug_newcomb@fws.gov>; gdal-dev@lists.osgeo.org<br>
<b>Subject:</b> EXTERNAL: Re: [EXTERNAL] [gdal-dev] Shape update/addition for Ceres<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" align="left" width="100%" style="width:100.0%">
<tbody>
<tr>
<td style="background:#A6A6A6;padding:0in 0in 0in 0in"></td>
<td width="100%" style="width:100.0%;background:#EAEAEA;padding:0in 0in 0in 0in;aspect-ratio: revert !important;background:revert !important;block-size: revert !important;border:revert !important;bottom: revert !important;color:revert !important;color-scheme: revert !important;content-visibility: revert !important;cursor:revert !important;direction:revert !important;display:revert !important;font-size:revert !important;height:revert !important;hyphens: revert !important;letter-spacing:revert !important;line-height:revert !important;margin:revert !important;opacity: revert !important;order: revert !important;outline: revert !important;overflow:revert !important;padding:revert !important;position:revert !important;resize: revert !important;rotate: revert !important;scale: revert !important;tab-size: revert !important;table-layout:revert !important;text-align:revert !important;text-indent:revert !important;text-orientation: revert !important;text-overflow: revert !important;text-shadow:revert !important;text-transform:revert !important;text-wrap: revert !important;top:revert !important;transition: revert !important;user-select: revert !important;vertical-align:revert !important;visibility:revert !important;white-space:revert !important;width:revert !important;word-break:revert !important;word-spacing:revert !important;writing-mode:revert !important;zoom: revert !important;word-wrap: break-word !important">
<div>
<p class="MsoNormal" style="mso-element:frame;mso-element-frame-hspace:2.25pt;mso-element-wrap:around;mso-element-anchor-vertical:paragraph;mso-element-anchor-horizontal:column;mso-height-rule:exactly">
You don't often get email from <a href="mailto:thare@usgs.gov">thare@usgs.gov</a>.
<a href="https://aka.ms/LearnAboutSenderIdentification">Learn why this is important</a>
<o:p></o:p></p>
</div>
</td>
<td style="background:#EAEAEA;padding:0in 0in 0in 0in;aspect-ratio: revert !important;background:revert !important;block-size: revert !important;border:revert !important;bottom: revert !important;color:revert !important;color-scheme: revert !important;content-visibility: revert !important;cursor:revert !important;direction:revert !important;display:revert !important;font-size:revert !important;height:revert !important;hyphens: revert !important;letter-spacing:revert !important;line-height:revert !important;margin:revert !important;opacity: revert !important;order: revert !important;outline: revert !important;overflow:revert !important;padding:revert !important;position:revert !important;resize: revert !important;rotate: revert !important;scale: revert !important;tab-size: revert !important;table-layout:revert !important;text-align:revert !important;text-indent:revert !important;text-orientation: revert !important;text-overflow: revert !important;text-shadow:revert !important;text-transform:revert !important;text-wrap: revert !important;top:revert !important;transition: revert !important;user-select: revert !important;vertical-align:revert !important;visibility:revert !important;white-space:revert !important;width:revert !important;word-break:revert !important;word-spacing:revert !important;writing-mode:revert !important;zoom: revert !important;word-wrap: break-word !important;align: left !important">
</td>
</tr>
</tbody>
</table>
<div>
<div>
<div style="mso-element:para-border-div;border:solid #9C6500 1.0pt;padding:2.0pt 2.0pt 2.0pt 2.0pt;background:#E87E04">
<p style="background:#E87E04;border:none;padding:0in"><b>WARNING</b> - This email originated from an EXTERNAL SOURCE. Do not click any link and do not open attachments unless you can confirm the sender.<o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">Scott,<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:Aptos;color:black"> That spherical value of 470 km, as defined in ESRI's projection, was intended. We are still working with the IAU to update these rules, but when that projection
was defined, we used this rule:<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">If the IAU defined a "mean" radius for a body (see Table 6.0
<a href="https://astropedia.astrogeology.usgs.gov/download/Docs/WGCCRE/WGCCRE2015reprint.pdf#page=33" title="https://astropedia.astrogeology.usgs.gov/download/Docs/WGCCRE/WGCCRE2015reprint.pdf#page=33">
page 33</a> of the report), we default to that value as a sphere. <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">This value was provided to the IAU by Thomas Roatsch (DLR) from the Dawn Team.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">The Dawn team, which produced the control mosaic for Ceres, also used 470 km as a sphere for the final mosaic and digital terrain model (
<a href="https://astrogeology.usgs.gov/search/map/ceres_dawn_fc2_hamo_global_dtm_137m" title="https://astrogeology.usgs.gov/search/map/ceres_dawn_fc2_hamo_global_dtm_137m">
DTM</a>):<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">reference: <a href="https://doi.org/10.1016/j.pss.2016.05.011">
https://doi.org/10.1016/j.pss.2016.05.011</a><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">quote, <i>"Ceres' shape model was then used for the calculation of the ray intersection points, while the map projection itself was placed onto a reference sphere of Ceres with a mean radius of
470 km."</i><br>
image mosaic: <a href="https://astrogeology.usgs.gov/search/map/ceres_dawn_fc_global_mosaic_140m">
https://astrogeology.usgs.gov/search/map/ceres_dawn_fc_global_mosaic_140m</a></span><span style="font-family:Aptos"><o:p></o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">While it might seem strange to use a sphere, this is common for irregular shaped bodies. This is mostly true for bodies defined as a triaxial since mapping applications do not commonly support
triaxial map projections. The IAU defines these mean radii to help support interoperability across applications. We are working with the IAU and could update some of these rules. For example, I will say it is odd to see that Ceres is NOT defined as a triaxial,
but the Dawn Team and the IAU promote a "mean" radius. I'm sure we will revisit this in the future.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:Aptos;color:black"><br>
BTW, it doesn't mean you can't define your own projection for Ceres if you need to. But I would recommend matching the current best-of image mosaic and DTM.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">I hope that helps,<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black">Trent<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:Aptos;color:black"><o:p> </o:p></span></p>
</div>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="3" width="98%" align="center">
</div>
<div id="divRplyFwdMsg">
<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> Newcomb, Doug <<a href="mailto:doug_newcomb@fws.gov">doug_newcomb@fws.gov</a>><br>
<b>Sent:</b> Sunday, December 22, 2024 8:12 PM<br>
<b>To:</b> Reynolds, Scott <<a href="mailto:scott@agi.com">scott@agi.com</a>><br>
<b>Cc:</b> Hare, Trent M <<a href="mailto:thare@usgs.gov">thare@usgs.gov</a>><br>
<b>Subject:</b> Re: [EXTERNAL] [gdal-dev] Shape update/addition for Ceres</span> <o:p>
</o:p></p>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:Aptos;color:black">check with Trent Hare at USGS<o:p></o:p></span></p>
</div>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="3" width="98%" align="center">
</div>
<div id="x_divRplyFwdMsg">
<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> gdal-dev <<a href="mailto:gdal-dev-bounces@lists.osgeo.org">gdal-dev-bounces@lists.osgeo.org</a>> on behalf of Reynolds, Scott via gdal-dev <<a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>><br>
<b>Sent:</b> Saturday, December 21, 2024 9:17 AM<br>
<b>To:</b> <a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a> <<a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>><br>
<b>Subject:</b> [EXTERNAL] [gdal-dev] Shape update/addition for Ceres</span> <o:p>
</o:p></p>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
<p> <o:p></o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" style="background:yellow;border-collapse:collapse;box-sizing: border-box;border-spacing: 0px">
<tbody>
<tr style="height:15.75pt">
<td width="952" style="width:714.25pt;padding:0in 0in 0in 0in;height:15.75pt">
<p align="center" style="text-align:center"><b> This email has been received from outside of DOI - Use caution before clicking on links, opening attachments, or responding. </b><o:p></o:p></p>
</td>
</tr>
</tbody>
</table>
<p style="margin-bottom:12.0pt"><o:p> </o:p></p>
<p>As a user of GDAL in some of our products I’m trying to find a contact, probably/possibly at Esri, that could add a new entry for Ceres that uses the oblate parameters defined
<u><span style="color:#0563C1"><a href="https://astropedia.astrogeology.usgs.gov/download/Docs/WGCCRE/WGCCRE2015reprint.pdf"><span style="color:#0563C1">here</span></a></span></u> (487.3km, 446km). ESRI:104972 exists for the spherical definition (470 km).<o:p></o:p></p>
<p> <o:p></o:p></p>
<p>Thanks,<o:p></o:p></p>
<p>Scott<o:p></o:p></p>
<div style="border:solid #003333 1.0pt;padding:8.0pt 8.0pt 8.0pt 8.0pt;color:inherit" id="x_x_footer">
<p class="MsoNormal" style="background:#D5EAFF"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:red">Disclaimer</span></b><o:p></o:p></p>
<p style="text-align:justify;line-height:10.0pt;background:#D5EAFF"><span style="font-size:10.0pt;font-family:"times roman",serif">The information contained in this electronic message and any attachments to this message are intended only for the individual(s)
addressed in the message and may contain proprietary and confidential information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender and delete this message. WARNING: Computer viruses
can be transmitted via email. The recipient should scan this email before opening it. The company accepts no liability for any damage caused by any virus transmitted by this email.<o:p></o:p></span></p>
</div>
</div>
</div>
</div>
<div id="footer" style="background-color:#D5EAFF; border:1px solid #003333; padding:.7em; ">
<span style="font-size:12pt;font-weight:bold; font-family: 'times new roman'; color:#ff0000;">Disclaimer</span><br>
<p style="font-size:10pt;text-align:justify; line-height:10pt; font-family: 'times roman';">
The information contained in this electronic message and any attachments to this message are intended only for the individual(s) addressed in the message and may contain proprietary and confidential information. If you are not the intended recipient, you should
not disseminate, distribute or copy this e-mail. Please notify the sender and delete this message. WARNING: Computer viruses can be transmitted via email. The recipient should scan this email before opening it. The company accepts no liability for any damage
caused by any virus transmitted by this email. </p>
</div>
</body>
</html>