Bonnean projection

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Bonnean projection of the world, standard parallel at 45 ° N.
Bonnean projection with Tissotian indicatrix of the deformation.
World map by Bernard Sylvanus, 1511
Bonnean projection of the earth with coordinate grid

The Bonnesche projection is a fake cone-shaped map projection by the French cartographer and mathematician Rigobert Bonne . He developed this heart-shaped projection of the entire earth in 1752. The Bonnesche projection is sometimes also referred to as the modified Flamsteed projection. Another historical name is Dépôt de la guerre , which indicates its use in the French military.

properties

The Bonnesche projection is characterized by its area fidelity. The middle meridian is a straight line, while all other longitudes are complex curves. The latitudes run on concentric circles with the same distance 'parallel' to each other. The central meridian and parallels are true to length. A circle of latitude is always the circle of contact and lies transversely (perpendicular to the earth's axis). Projection was initially popular because of its equal area, but was later used only rarely because of its distortion. The smaller the land mass shown, the less distortion there is at the edges of the map. It is advisable to choose this projection only for areas north of the equator, unless the entire surface of the earth is to be displayed.

Similar projections

There are other heart-shaped (cordiform) projections. The Bonnesche projection is the successor to the Stab-Werner projection . Newer ideas are modifications of the Bonnean projection (Heart), mathematically more complex projections, projections composed of different types of projection (Amulet, Shield) or based on other projections (Bottomley 50 ° N).

The Bonnesche projection was used as the basis for the Dufour map, the oldest official map series in Switzerland from 1840.

Another application of the projection was the overview map of Central Europe (Bonne projection) 1: 750,000 of the Austrian Military Geographic Institute as part of the Franzisco-Josephinische Landesaufnahme .

Bonnean projection for the southern hemisphere

This projection is preferable to the normal Bonn projection if all areas shown can only be found south of the equator, unless the entire surface of the earth is to be displayed. The sinusoidal projection is recommended for maps showing areas north and south of the equator in one section . In order to represent the southern hemisphere as undistorted as possible, mathematically the heart is turned upside down (inverted heart-shaped, obcordate). This calculation is known as the South Oriented Bonne Projection or the Southern Hemisphere Bonne Projection . On a map that shows the northern hemisphere in the Bonneschen projection and the southern hemisphere in the southern projection, the equatorial lines only touch at one point.

Web links

Commons : Bonnesche Projektion  - collection of images, videos and audio files

Individual evidence

  1. ↑ Reference system and map projection of the Dufour map (CH1840). (No longer available online.) Archived from the original on September 22, 2016 ; accessed on September 22, 2016 .
  2. ↑ C. Bohn: The land survey . A teaching and manual. Springer, Berlin, Heidelberg 1886, p. 696, 757 , doi : 10.1007 / 978-3-642-51409-8 ( limited preview in Google Book Search [accessed August 5, 2018] Reprint of the historical edition, ISBN (softcover): 978-3-642-51290 -2, ISBN (eBook): 978-3-642-51409-8).
  3. ^ A b c Majid Husain: Concise Geography . TATA McGraw Hill Education, New Delhi 2011, ISBN 978-0-07-107479-7 , chap. 11 , p. 19 ( limited preview in Google Book Search [accessed August 4, 2018]).
  4. ↑ Geocart Projections - Heart. mapthematics.com, accessed August 5, 2018 .
  5. ↑ Geocart Projections - isoperimetric cordiform. mapthematics.com, accessed August 5, 2018 .
  6. ↑ Geocart Projections - Amulet. mapthematics.com, accessed August 5, 2018 .
  7. ↑ Geocart Projections - Shield. mapthematics.com, accessed August 5, 2018 .
  8. ↑ Bottomley 50 ° N. In: kartenprojektionen.de. Tobias Jung, accessed on August 5, 2018 .
  9. ↑ Guillaume-Henri Dufour: The Swiss National Surveying, 1832–1864. History of the Dufour map, etc . Verlag Stämpfli, Bern 1896, British Library , Historical Print Editions, London 2011, ISBN 1-241-38017-1 .
  10. ^ Ernst Hofstätter: Contributions to the history of the Austrian regional surveys: An overview of the topographical survey procedures, their origins, their developments and organizational forms of the four Austrian regional surveys. Published by the Federal Office for Metrology and Surveying . 2 volumes. Vienna 1989, DNB 943727200 . P. 169.
  11. ^ Stuart Pearson: Australian Contributions to the History of Military Geography . In: S. Pearson S, J. Holloway, R. Thackway (Eds.): Australian Contributions to Strategic and Military Geography. Advances in Military Geosciences . Springer, Cham, 2018, ISBN 978-3-319-73407-1 , pp. 13–34 , doi : 10.1007 / 978-3-319-73408-8_2 (cited south-oriented Bonnesche projection by Griffith Taylor 1920 with Australia in the middle. Image ).
  12. ↑ Griffith Taylor: Australian Meteorology: A Text-book including Sections on Aviation and Climatology . Clarendon Press, Oxford 1920, pp. 107 (Fig. 91), 274 (Fig. 216) ( online ).
  13. ↑ SuperMap (ed.): Projection Type enumeration . ( Online [accessed August 4, 2018]).
  14. ↑ Guillaume Le Testu: Mappemonde en deux hémisphères . 1566 (French, online [accessed August 4, 2018]).
  15. ↑ Guillaume Le Testu: World Map in two Hemispheres (Bonne Projection) . 1566 (English, online [accessed August 4, 2018]).