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<p>The original question in this "thread" was with respect to projection bounds, and specifically UTM:</p>
<p> </p>
<p><em><strong>"Is there a way to find out the bounds of a given projection?<br>
Let’s say I have a given projection (UTM) and have a point (supposedly in the same utm) but I want to find out if that point is within the bounds of the projection."
</strong></em></p>
<p> </p>
<p> I see this has devolved to a discussion on the variation of datum shifts with respect to geographic areas. The "new" topic needs to recognize datum shifts accomplished with MREs, NTv2, NadCon, 3-parameter rigid-body geocentric shifts and 7-parameter Molodensky
and Bursa-Wolf shifts. </p>
<p> </p>
<p>Each tool works within its intended design area, but DOES require some basic knowledge of geodesy for proper implementation. If you're going to teach GIS, you need to first teach the basics of the geodetic foundation of the system.</p>
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<p><font face="Copperplate Gothic Bold">Clifford J. Mugnier, c.p., c.m.s.</font></p>
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<div style="DIRECTION: ltr" id="divRpF960386"><font color="#000000" size="2" face="Tahoma"><b>From:</b> proj-bounces@lists.maptools.org [proj-bounces@lists.maptools.org] on behalf of Cusick, Joel [joel_cusick@nps.gov]<br>
<b>Sent:</b> Friday, October 25, 2013 1:17 PM<br>
<b>To:</b> proj@lists.maptools.org<br>
<b>Subject:</b> Re: [Proj] Proj Digest, Vol 113, Issue 8<br>
</font><br>
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<div dir="ltr">It is my experience that defined descriptive bounds tagged to coordinate systems has caused great confusion in GIS circles - especially for "legacy" systems.
<div><strong style="BORDER-BOTTOM: 0px; BORDER-LEFT: 0px; PADDING-BOTTOM: 0px; LINE-HEIGHT: 19px; MARGIN: 0px; OUTLINE-STYLE: none; OUTLINE-COLOR: invert; PADDING-LEFT: 0px; OUTLINE-WIDTH: 0px; PADDING-RIGHT: 0px; FONT-FAMILY: Arial,Helvetica,sans-serif; COLOR: rgb(77,77,77); FONT-SIZE: 14px; VERTICAL-ALIGN: baseline; BORDER-TOP: 0px; BORDER-RIGHT: 0px; PADDING-TOP: 0px">NAD_1983_To_WGS_1984_2</strong><span style="LINE-HEIGHT: 19px; FONT-FAMILY: Arial,Helvetica,sans-serif; COLOR: rgb(77,77,77); FONT-SIZE: 14px">
for example, tagged for use in the Aleutians still is being used today with modern positional tools (like GPS).</span><br>
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<div><span style="LINE-HEIGHT: 19px; FONT-FAMILY: Arial,Helvetica,sans-serif; COLOR: rgb(77,77,77); FONT-SIZE: 14px">Over the years, ESRI has refined their use of these and we welcome these changes. See the red text on this page.</span></div>
<div><a href="http://support.esri.com/cn/knowledgebase/techarticles/detail/24159" target="_blank">http://support.esri.com/cn/knowledgebase/techarticles/detail/24159</a><span style="LINE-HEIGHT: 19px; FONT-FAMILY: Arial,Helvetica,sans-serif; COLOR: rgb(77,77,77); FONT-SIZE: 14px"><br>
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<div class="gmail_quote">On Fri, Oct 25, 2013 at 9:00 AM, <span dir="ltr"><<a href="mailto:proj-request@lists.maptools.org" target="_blank">proj-request@lists.maptools.org</a>></span> wrote:<br>
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1. Re: Projection bounds question (Hermann Peifer)<br>
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Message: 1<br>
Date: Thu, 24 Oct 2013 20:11:10 +0200<br>
From: Hermann Peifer <<a href="mailto:peifer@gmx.eu" target="_blank">peifer@gmx.eu</a>><br>
Subject: Re: [Proj] Projection bounds question<br>
To: "PROJ.4 and general Projections Discussions"<br>
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On 2013-10-24 17:57, Richard Greenwood wrote:<br>
> Coordinate systems do not generally have defined bounds although there<br>
> may be laws that govern where a given coordinate system is to be used.<br>
> In theory, you could represent any place on the earth in any coordinate<br>
> system.<br>
><br>
<br>
(Ahem)<br>
<br>
How would you represent a point at 52S 170W in ETRS89/LAEA Europe, also<br>
known EPSG:3035? 52S 170W happens to be the antipodal point of the<br>
coordinate system's projection centre.<br>
<br>
Hermann<br>
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-- <br>
<div dir="ltr">Joel Cusick
<div>GIS Specialist</div>
<div>c: 907.280.9724 w: 907.644.3549</div>
<div>240 W. Fifth Ave. Anchorage AK 99501</div>
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