<div dir="ltr">Dave,<div><br></div><div>You need time tagging of observations in order to transform from a global reference frame (WGS84, ITRF) to a plate fixed (NAD83, ETRS89).</div><div><br></div><div>For a next generation of dynamic datums, this will be even more of an issue, although in ways that are not totally clear as yet.</div><div><br></div><div>Cheers,</div><div>Thomas</div></div><div class="gmail_extra"><br><div class="gmail_quote">2017-06-26 15:17 GMT+02:00 caress <span dir="ltr"><<a href="mailto:caress@mbari.org" target="_blank">caress@mbari.org</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thomas,<br>
<br>
Thanks. Looking again at the discussion thread it should have been clear to me that the functions used by MB-System are not changing.<br>
<br>
With respect to time dependence, we certainly are doing repeated seafloor surveys that resolve both lateral and vertical deformation. For instance, on Axial seamount our repeated 1-m-scale bathymetry surveys show ~10-m wide fissures that opened coincident with the 2011 and 2015 eruptions, and annual repeat surveys are measuring the several tens of cm of uplift each year associated with the inflation of the subsurface magma reservoir. However, I’m not sure how having time dependence in Proj can tie into our representing or modeling this deformation. Any advice would be welcome.<br>
<br>
Cheers,<br>
Dave<br>
<div class="HOEnZb"><div class="h5"><br>
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<br>
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> On Jun 24, 2017, at 8:57 AM, Thomas Knudsen <<a href="mailto:knudsen.thomas@gmail.com">knudsen.thomas@gmail.com</a>> wrote:<br>
><br>
> Dave,<br>
><br>
> We are NOT changing the API of a core dependency of yours. We are adding a new, more coherent one, in anticipation of a growing need of fully dynamic datum transformations.<br>
><br>
> The new API in proj.h is orthogonal to the classic API in proj_api.h<br>
><br>
> I do, however, expect that you will need the functionality exposed in the new API - if not now, then in a few years time.<br>
><br>
> /Thomas<br>
><br>
> 2017-06-24 10:46 GMT+02:00 caress <<a href="mailto:caress@mbari.org">caress@mbari.org</a>>:<br>
><br>
> As the architect of a package, I have similar feelings about anyone that changes the API of a core dependency.<br>
><br>
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David W. Caress<br>
Software Engineer<br>
<br>
Monterey Bay Aquarium Research Institute<br>
7700 Sandholdt Road<br>
Moss Landing, CA 95039<br>
<br>
<a href="mailto:caress@mbari.org">caress@mbari.org</a><br>
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<br>
Phone: <a href="tel:831-775-1775" value="+18317751775">831-775-1775</a><br>
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