<html><body name="Mail Message Editor"><br>On Mar 20, 2009, at 2:34:00 AM, "Mikael Rittri" <Mikael.Rittri@carmenta.com> wrote:<br><blockquote style="padding-left: 5px; margin-left: 5px; border-left-width: 2px; border-left-style: solid; border-left-color: blue; color: blue; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: -webkit-monospace; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><pre>A) For some projections, a parameter for central latitude can be given,
but it does not really affect the shape of the map - it just creates
an extra offset in the northing values (in addition to the offset
due to the FalseNorthing).
My question: is there an established terminology for such
a central latitude?
When documenting projections, I would like to write something
like "the central latitude can be specified but is just cosmetic",
with a link to a glossary entry for "cosmetic central latitude".
But is "cosmetic" the best word? </pre></span></blockquote>
<div><br></div><div>Being merely a coordinate translation, most of the small-scale map projection literature ignores the "central latitude". Snyder includes it explicitly in his formulations, referring to it as the "latitude of origin" and denoting it as φ₀. See, for example:<br></div><div><br></div><div>Snyder, J.P. 1987. Map Projections — A Working Manual, p. 100. (US Geological Survey Professional Paper 1395). US Government Printing Office, Washington D.C.</div><div><br></div><div>Deetz & Adams (Elements of Map Projection) includes what is effectively the radius of the latitude of origin in their formulations of conic projections, but do not attempt to name it.</div><div><br></div><div>"Latitude of origin" seems sufficient and unambiguous. The central meridian and latitude of origin project to the cartesian origin. Rather than using the term "cosmetic" I would note that it is just a simple translation that does not bear on the geometry of the projection, and thenceforth label it the "latitude of origin".<div><div><br></div><div>Regards,</div><div>— daan Strebe<br><blockquote style="padding-left: 5px; margin-left: 5px; border-left-width: 2px; border-left-style: solid; border-left-color: blue; color: blue; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: -webkit-monospace; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><pre></pre></span></blockquote><br><div><br></div></div></div></div><div class="aol_ad_footer" id="uC6AEAB906C8C439A8F4B1358C4F96B80"></div></body></html>