Hillshade

[Ingrid Campbell]

HI there- 

So, I feel like, even though I do not have the same color ramp as the one in the video tutorial, my hillshade, especially for my 10 m DEM does not look as good as the one in the video.  Below is a screen shot of my 10m DEM overlaying the hillshade and then a screen shot of just the hillshade. Can you see the almost gridlike appearance of the hillshade? Those little gridlike lines do not seem to be in the video tutorials.  Am I just seeing things, or do others' hillshade look like mine? 

Thanks!

[Shannon Wing Belmont]

This is something we typically see in the 30m NED data from the AGRC.

It is an artifact of the sampling process the AGRC did to the data. I haven't seen it rear it's ugly head with the 10m data. But that's not necessarily meaningful. It could be some small glitch that occurred during the hillshade creation? have you tried running it again?

It could also be something in the AGRC data. If this were for your research I'd tell you to go to the USGS seamless server (now officially the National Map) and download the data from them directly. That should fix the problem.

If you are curious - check it out here.   This is the main page where instructions for using the interface can be found.

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Shannon Belmont

Quinney College of Natural Resources
Utah State University
5210 Old Main Hill
Logan, UT 84322-5210

[Alice de Anguera]

My 10 meter NED hillshade has some grid issues too.

Alice

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From: Shannon Wing Belmont <swb....@gmail.com>
To: usu-nr-...@googlegroups.com
Sent: Wednesday, March 13, 2013 1:53 PM
Subject: Re: Hillshade

[Bryan Christensen]

I have the same shadowy grid also.  I'm wondering if we need to make all the color ramp settings among all the hillshades the same ( like we did for all the dem displays. 

Sent from my iPhone

[Shannon Wing Belmont]

Hi Bryan,
Hillshades should always be displayed with a black/white color ramp (unless you have a very good and defensible reason not to).
The default color ramp associated with hillshades is the one they should be left with.
Remember that a hillshade doesn't contain information about the surface itself. it is a visualization tool. The raster cell values are in the range of 0-255 which only represent the colors from white to black (=brightness).