Convert a TIF to a PNG (or other Wilbur-friendly format)

[acrosome]

So, I finally got a lovely 7.5arcsec heightmap for North America churned through QGIS and spat out as a TIF. This monster is 6.4GB, 72k x 48k px. I'm pretty sure that Wilbur will choke to death on it, but I want to try anyway. (I want to generate some contour lines.)

I can load the TIF into GIMP, which does not choke to death on it, but it looks awfully faint- it's much, much more faint than it looks on QGIS, for some damned reason. I'm assuming that it's because the scale range was only -79 to 5634 on the original in QGIS and the TIF file is now 16 bit or something?

So, how do I fix that faint appearance? Then, I assume that I can just export it as a PNG from GIMP, which is easy. But I have to fix it first.

Ideas?

[acrosome]

Never mind- I figured out how to use the -scale operator in the Translate function. It's good now.

Now to export a PNG and test the limits of Wilbur... Mwa-ha-ha!

EDIT- Oh, yeah. Wilbur dies horribly. I guess I need to learn QGIS...

[Redrobes]

If you just want contour lines from it then you can do that in Gimp. Take a copy of the greyscale height map and blur it slightly. Then go into the color curves section and set up a curve so that it near black is black then dark grey goes white then not so dark grey goes black again then mid grey goes white then lighter mid grey goes black and keep going all the way up to bright colours.

Your map then looks like a zebra striped version. Then use the find edges using Sobel function and it will pop it out in contours.

This one would be a good one to add to my image processing apps...