[GRASS-dev] Scale display in GRASS Monitor

Glynn Clements glynn at gclements.plus.com
Thu Sep 28 11:18:07 EDT 2006


Hamish wrote:

> > How about having a global conversion factor that can be calibrated,
> > e.g. as an environment variable.
> > 
> > Give the user the option to manually calibrate that: show him a bar or
> > set of bars, ask him to measure it/them using a ruler and report the
> > results. That would be neat at graphical startup screens. We can even
> > have our own (reliable) measures to test against absurd values.
> > 
> > Just an idea. It's rather odd that no GIS implements this kind of
> > artisanal method...
> 
> the Gimp used to let you do this when you installed it, ie displayed a
> ruler on the screen and asked you to measure it. AFAICT in the Gnome
> "dumming down" efforts this has been abandoned, or at least isn't
> presented as part of the new install wizard.
> 
> I'm afraid I don't see the benefit, but do see a lot of problems.

The main problem being that the user will probably forget to update
the information if they change the size of the desktop or switch
monitors.

But that's a minor issue. If we force the user to specify the
resolution, all of our problems go away (there are still problems, but
they're not *our* problems).

I can see the point in having a scale printed on paper maps where
people actually measure distances on the map using dividers and a
ruler. I doubt that people do this with a monitor (dividers probably
aren't particularly kind to the surface of the monitor, and d.measure
is likely to be easier to use).

-- 
Glynn Clements <glynn at gclements.plus.com>




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