Albers projection

The Albers conic projection is an equal-area map web design, in which the earth's surface is projected onto a cone. It touches the cone, more truncated cone, the surface in either a parallel ( standard parallel ) or cuts it in two standard parallels. The latter method is almost exclusively used. The tip of the cone is usually on the Earth's axis. Good is this projection for regions with a large east-west than north- south extent. The main features are:

• Equal area, ie area contents are displayed correctly;
• Meridians are straight lines have equal distances to each other and intersect parallels at right angles;
• Wide channels are parallel to each other, the distances the same, however, vary;
• Parallel interface are mapped isometrically.

History

Heinrich C. Albers (1773-1833), son of a merchant from Lüneburg, published in November 1805, this form of conical figure in a paper in the journal Monthly Zach's correspondence and has since been regarded as the inventor. Albers were shortcomings in the presentation by Patrick Murdoch († 1774) prior conic projection noticed, are not represented in equal area of the patches. Back in February, he wrote in the same journal on the draft of Murdoch:

" Now I wonder what it may help that the whole cone zone with the ball zone has the same content when each zone differs significantly from it. After all, bey every country that is not limited by the meridians and parallels itself, the card can never specify the true surface area in this way; and where such exists, by four right-angled lines limited land? "

In the publication of his own design Albers concludes with the words:

"You can see that this my cone Projection all the advantages of Murdoch'ischen granted without allowing more of its shortcomings, are as inevitable. As also indicated the advantages of me [ ... ] mine alone peculiarly belong. So I think me to be able to flatter right to have loosed the problem of a possibly perfect cone Projection first satisfying. "

Cards with Albers projection

In 1806, Albers drew his charter of East India on the basis of Arrowsmith's Map of India from 1804., It is questionable whether he has applied for this purpose its own projection. She appeared in Gotha as a single sheet. A contemporary wrote that the card had " a pure neat stitch, very legible font, and a very clear and obvious boundaries - Illuminirung ". The following year, Albers anonymously peer reviewed Arrowsmithsche the map used in the monthly correspondence. Accompanied his map publishing efforts were unsuccessful. In the temporal proximity card then appeared as a supplement to a reprint of the review on six leaves. After a few years the card is again, along with a listing of the area of ​​individual Indian territories reprinted in Zimmermann's Handbook of traveling, " as they used to be-ing seems to be less than it deserves it."

1809-1818: The Lobensteiner cartographer Christian Gottlieb Reichard took over the projection probably first. From him are several, published every few years known maps that are based on Albers projection. The earliest example is Reichard's map of the United States of North America in the Albers'schen Projection and was published in 1809 in Nuremberg. Then the projection waned.

It was not until the turn of the century seems to have rediscovered the work of Albers. The Military Geographical Institute in Vienna, devised a scale to 40 sheets New General Map of Europe 1: 750,000 with projection The Albers. By 1903, two sheets were issued and five more in the works, a total of twelve sheets were completed. The ninth and last edition of Sohr -Berghaus ' Atlas hand over all parts of the world appeared in the 1900s for the first time with cards that were designed by Albers projection.

Already in the 1920s had Oscar Adams at the U.S. Coast and Geodetic Survey of speaking " a equal-area representation ", " which is as good as any other and better in many ways than any other ." Thereafter, the USGS used the Albers projection exception for maps of the fifty U.S. states in the National Atlas from 1970 with standard parallels at 29.5 ° and 45.5 ° N B (excluding Alaska and Hawaii). The revised map showing the USDA climate zones appeared in 1990.