[Proj] Common term for geographic and projected coordinates?
Gerald I. Evenden
geraldi.evenden at gmail.com
Wed Feb 4 10:22:57 EST 2009
On Wednesday 04 February 2009 5:19:12 am Mikael Rittri wrote:
> Gerald wrote:
> > A second issue arose and is the preferred or official designation of
> > lat-lon-h coordinates. Is geographic or geodetic preferred? I have a
> > tendency to use the two designations interchangeably and mix them freely
> > in emails and documentation.
> > Anyone want to nit-pick over this usage. :-)
> Well, h is a hairy issue, with all the different kinds of height.
> But for lat-lon, both "geographic coordinates" and "geodetic coordinates"
> would be correct, as far as I understand it.
> But "geographic coordinates" is probably more common (Google gives 585
> 000 hits for "geographic coordinates", and only 19 700 hits for "geodetic
> Now to my own question: is there a general term that includes both
> geographic coordinates (lat-lon) and projected coordinates
> (easting-northing), as opposed to pixel 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).
> As you see, I haven't found a snappy way to express it.
> I can only think of "georeferenced coordinates", but is there a better
Isn't this just a "scale" issue. That is, you are scaling and translating the
XY from the projected data to the units of the display device. The only
added hassle is that a pixel represents an area rather than a point.
To go from pixels back to the projected data and eventually to geographic data
is merely unscaling and untranslating and then inverse projection.
Why isn't "scale-translation to and from display units" a useful phrase. May
not be snappy but seems clear to me and, I might add, I don't think we need
any more snappyness. ;-)
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist
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