[GRASS5] r.in.png error?

Glynn Clements glynn.clements at virgin.net
Sat Sep 4 02:31:13 EDT 2004

Namnath, Sharyn wrote:

> > However, it's debatable whether you should be re-importing images
> > which were created using the PNG driver into GRASS. For
> > zooming/panning around a map (or series of maps), you would normally
> > create a new PNG file each time, by the same means that the original
> > PNG file was created.
> Ideally, this would be the case, but some of the data files are large areas
> such as continents. I'd like to be able to show the world first, then the
> user click on any place in the map and it zooms into an area such as a
> continent or perhaps something a little closer (at some point I imagine I'll
> have to create another higher resolution map of that area as they get
> closer). As they keep clicking, they zoom in closer and closer until they
> get to a country or state or city.

Zooming in on a rendered image will simply magnify the individual
pixels. E.g. if you render a continent-scale image, then enlarge it by
a factor of ten, each pixel in the original image will become a 10x10
square in the zoomed image.

You will get much better results if each image is created directly
from the original high-resolution data.

Glynn Clements <glynn.clements at virgin.net>

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