AUTOREPLY [Proj] Equations for Apianus II, sinusoidal, cylindric...

jens.schwarz at alpstein.de jens.schwarz at alpstein.de
Tue Aug 21 02:20:09 PDT 2007




Sehr geehrte Damen und Herren,

da ich mich bis einschließlich 24.08.07 im Urlaub befinde,
ist es mir leider nicht möglich Ihre e-mail persönlich zu beantworten.

Ab Montag,27.08.07 bin ich wieder im Büro und werde mich baldmöglichst
um Ihr Anliegen kümmern. 

In dringenden Fällen wenden Sie sich bitte an meinen Kollegen, Herrn Martin Soutschek, unter  martin.soutschek at alpstein.de

Vielen  Dank für Ihr Verständnis.

Mit besten Grüßen aus Immenstadt

Jens Schwarz
Fachbereich Technologie & Produkte
      
Alpstein GmbH                      
Missener Str. 18                   
87509 Immenstadt                   
                                 
fon  08323-8006-0 
fax  08323-8006-50
www.alpstein.de
info at alpstein.de



Because Oscar asked “Where are the equations”, and so that that other person 
won’t think that I’m being like Fermat, I’m posting the equations for all 
four of the projections that I’ve recommended that have the linearly 
interpolable positions property.

I’ve already posted the equations for the graduated equidistant cylindrical, 
and in this posting are the equations for Apianus II (equally-spaced 
elliptical), the sinusoidal, and the ordinary equidistant cylindrical.

The other day, for the graduated equidistant cylindrical, I had the map 
co-ordinates’ origin, and 0 longitude, at the west edge of the projection, 
but for the remaining three, today, I’m saying it differently, in a way 
that’s more generally useful, so that I only have to say that part once, for 
all three projections.

The origin of the map co-ordinates is at the intersection of the equator and 
the central meridian.

“Lat” means latitude in degrees, positive if north, and negative if south.

“Lon” means longitude in degrees, with respect to the central meridian, 
positive if east of the central meridian, negative if west of the central 
meridian.

That applies for all of the following three projections.

Apianus II:

Y = R*Lat*(pi/180)

A = pi*R

X = sqr(A*A-4*Y*Y)*(lon/180)

Sinusoidal:

Y = R*Lat*(pi/180)

X = R*Lon*(pi/180)*cos(Lat)

Ordinary equidistant cylindrical:

Y = R*Lat*(pi/180)

X = R*Lon*(pi/180)

Michael Ossipoff


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