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I received “Hillshade” data that I'm trying to use in QGIS.

When I check the "Pseudocolor" option under "Color map", I get many colors, apparently corresponding to the terrain, though it doesn't jump out in an intuitive way.

"Freak out" also does that, w/ a different color scheme. (Don’t know if these options came with QGIS or with my data.) But "Colormap" doesn't show up at all, and Grayscale is just uniformly gray.

I expected grayscale to exhibit shades that would make the terrain stand out intuitively - but I don't really know what to expect.

Any idea what my problem might be?

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If what you have is a hillshade you have shadow values ranging from 0 to 255. The best way to display it is gray scale and strectched min to max. What you have to understand is that you do not have elevation values in a hillshade raster. –  Gerardo Jimenez Feb 14 '13 at 14:25

2 Answers 2

up vote 2 down vote accepted

In addition to what Brad said, if you click the radio button on the Style tab for "Use standard deviation" and set the Contrast Enhancement to "Stretch To MinMax", you should be able to view your raster in grayscale. After applying the constrast stretch, the "Custom min/max values" fields will be filled in, and you can further refine the stretch. You can also load min/max values from the band using the "Load" button. The grayscale image will be the same thing you see in Pseudocolor or Freak Out mode, but, you know, grayer.

If you want to create an actual hillshade, use the Raster > Analysis > DEM (Terrain Models) tool.

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Thanks all. Kind of complicated stuff, I guess. –  TVZ Feb 14 '13 at 19:23

If you choose the colormap option on the Style tab then go to the colormap tab. Youmight search for "qgis colormap style" because I know there are some pre-built by users.
But to build your own

  1. you can add 2 discrete entries with the top and bottom colors that you want the palette to be in. (don't worry about the values or labels.
  2. select the number of classifications you want, equal interval will work, and then classify.
  3. After you get the basic look (as foar as smoothing, palette and so forth) you can go to each value and change the value, color, and label for each.

Play with it.

colormap

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