[Xastir] Re: Bounding boxes [Re: USGS maps no longer free]

[Curt Mills, WE7U]

On Mon, 6 Oct 2003, Curt Mills, WE7U wrote:

> On Mon, 6 Oct 2003, Tom Russo wrote:
> 
> > And now that I think about it, the data listed by listgeo are probably the
> > corner coordinates of the entire image, not the data for the map collar --- 
> > therefore making their use in an FGD file pointless.
> > 
> > The best way to get the bounding data that allows stripping off the
> > map collar would be to look at the map itself and pick off the
> > lattitude of the top and bottom neatlines, and the longitude of the
> > left and right neatlines.  Those will, in all probability, be
> > multiples of 7.5m, 15m, etc., depending on whether they're 1:24000,
> > 1:100000, etc.
> 
> Yes.  _That_ is the correct way to do it.  The *.fgd file is used for
> exactly that purpose in Xastir:  Chopping at the map neat lines.
> 
> It's also used for stretching the UTM projected image into a
> rectangle.

Oh yea, in case you didn't infer it from this last message, ignore my
previous message about averaging the corner values.  That's the wrong
way to do it.

Curt, WE7U.				archer at eskimo.com
http://www.eskimo.com/~archer
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