[Gdal-dev] Tilting of 7.5" Digital Elevation Models

Curt, WE7U archer at eskimo.com
Wed Aug 18 12:33:26 EDT 2004

On Wed, 18 Aug 2004, Ed McNierney wrote:

> They're not tilted, they're projected.  In the UTM projection the
> central meridian (for that zone) is "straight up" in the projection -
> meridians to the west of it will "tilt" to the right and those to the
> east will "tilt" to the left.  But they're not tilted, they're curved,
> and the degree of "tilt" also depends on the latitude.

Not only that, the bottom and top edges are curved, not straight,
and the top will be shorter than the bottom in the northern
hemisphere, opposite in the southern hemisphere.  At least if you're
trying to draw that projection onto a lat/long map screen it'll look
like that.

Curt, WE7U			         http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
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