[Proj] Common term for geographic and projected coordinates?

Karney, Charles ckarney at Sarnoff.com
Wed Feb 4 13:37:57 EST 2009

> From: Mikael Rittri [Mikael.Rittri at carmenta.com]
> Date: Wednesday, February 04, 2009 05:19
> Subject: [Proj] Common term for geographic and projected coordinates?
>    I am trying to document a method that tranforms pixel coordinates
> to either projected or geographic coordinates, depending on whether
> the window is presented with a map projection or just as lat-lon (all
> right, Pseudo Plate Carrée).

In the vision world, the conversion for "world" coordinates to pixels is
accomplished by a "camera matrix"


In general this is a projective map from 3d to 2d.  The simple case
you're considering is a similarity transform.  The transformation from
pixel to projected coordinates is given by the inverse of the camera
Charles Karney <ckarney at sarnoff.com>
Sarnoff Corporation, Princeton, NJ 08543-5300

URL: http://charles.karney.info
Tel: +1 609 734 2312
Fax: +1 609 734 2662

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