睇艾伯斯投影嘅原碼

[[Image:Usgs map albers equal area conic.PNG|frame|right|艾伯斯投影。雖然話睇落去好似咁鬼怪噉，但係呢兩個標準參數之間係未出現過變到離嗮譜嘅。]]
[[File:Albers projection SW.jpg|450px|thumb|地球嘅艾伯斯投影]]

'''艾伯斯投影'''（{{jpingauto|ngaai6 baak3 si1 tau4 jing5}}；{{lang-de|'''Albers-Kegelprojektion'''}}）；第個名係'''等積圓錐投影'''（{{jpautocore|deng2 zik1 jyun4 zeoi1 tau4 jing5}}） ；佢係由德國嘅科學家—海賢力·C·艾伯斯—喺1805年用兩條平行線提出嘅[[等面積]][[圓錐]]嘅[[地圖投影]]。雖然佢提出嘅曬士同形狀方面，到而家為止都冇固定用法，但係喺呢兩個標準參數之間係未出現過變到離嗮譜嘅。

艾伯斯投影係最先喺加拿大[[卑詩省]]嗰度提出嘅一項標準投影<ref>{{引網 |url=http://www.for.gov.bc.ca/hts/risc/pubs/other/mappro/map.htm#1 |title=British Columbia |access-date=2015年1月29號 |archive-url=https://web.archive.org/web/20140314032421/http://www.for.gov.bc.ca/hts/risc/pubs/other/mappro/map.htm#1#1 |archive-date=2014年3月14號 |dead-url=yes }}</ref>，而且呢個單獨投影重俾[[育空地區]]嘅政府用咗<ref>{{cite web|title= Support & Info: Common Questions |url= http://www.geomaticsyukon.ca/info/common-questions |work= Geomatics Yukon |publisher= Government of Yukon |accessdate= 15 October 2014 }}</ref>，甚至重俾[[美國地質調查局]]同埋[[美國人空調查局]]攞咗佢嚟用<ref>{{cite web |title=Projection Reference |publisher=Bill Rankin |url=http://www.radicalcartography.net/?projectionref |accessdate=2009-03-31 |archiveurl=https://web.archive.org/web/20090425214731/http://www.radicalcartography.net/?projectionref |archivedate=2009-04-25 |deadurl=no }}</ref>。

史乃達喺1395年出嘅一本書嗰度<ref name=snyder>{{Cite book| author=Snyder, John P. | title=Map Projections &ndash; A Working Manual. U.S. Geological Survey Professional Paper 1395 | publisher =United States Government Printing Office, Washington, D.C. | year=1987}} 呢篇嘢可以喺[http://pubs.er.usgs.gov/pubs/pp/pp1395 呢度下載嚟睇]</ref>嘅第14節嗰度已經寫咗呢項計劃嘅方程式出嚟。而呢項計劃就係從波形標準座標度，可以轉化艾伯斯投影嘅等面積公式出嚟<ref>
{{cite web |url=http://mathworld.wolfram.com/AlbersEqual-AreaConicProjection.html
|title=Albers Equal-area Conic Projection
|accessdate=2013-05-04
|work=Wolfram MathWorld
|publisher=Wolfram Research
|last=Weisstein |first=Eric 
}}</ref>如估λ同λ<sub>0</sub>係經度嘅話，噉φ嚟做經度，φ<sub>0</sub>嚟做緯度；或者係攞φ<sub>1</sub>同φ<sub>2</sub>嚟做緯度高出嘅標準參數公式出嚟：

如估
:<math>x = \rho  \sin\theta </math>
:<math>y = \rho_0 - \rho  \cos\theta </math>

噉
:<math>n = {\tfrac12} (\sin\varphi_1+\sin\varphi_2) </math>
:<math>\theta = n(\lambda - \lambda_0) </math>
:<math>C = \cos^2 \varphi_1 + 2 n \sin \varphi_1 </math>
:<math>\rho = \frac{\sqrt{C - 2 n \sin \varphi}}{n} </math>
:<math>\rho_0 = \frac{\sqrt{C - 2 n \sin \varphi_0}}{n} </math>

==睇埋==
{{Portal|地圖冊}}
* [[地圖投影一覽]]

==註==
{{reflist}}

==出面網頁==
*[http://mathworld.wolfram.com/AlbersEqual-AreaConicProjection.html Mathworld's page on the Albers projection]
* [http://www.radicalcartography.net/?projectionref Table of examples and properties of all common projections], from radicalcartography.net
*[http://www.environmentyukon.gov.yk.ca/geomatics/techweb/yt-albers-projection.html Yukon Albers Projection]
* [http://www.uff.br/mapprojections/Albers_en.html An interactive Java Applet to study the metric deformations of the Albers Projection]

[[Category:整圖投影]]
[[Category:等面積投影]]