Yeah, I didn't see those artifacts until I looked at it again. But I moved on to fixing the "distinct ring" of brown by redoing the color ramp.
The maps were created using ArcMap at work by exporting a Terrain, Colored, and Hillshade layers. Then, at home, I used Photoshop (an old and decrepit version 6 but it still works!!) to make the image.
Then I tried another experiment with some simple Photoshop techniques to compare with maps created with ArcMap. The attached images are listed below.
HypsoExper02am.jpg & HypsoExper03am.jpg - 2nd and 3rd experiments created solely with the layers Colored and Hillshade exported from ArcMap.
HypsoExper02ps.jpg & HypsoExper03ps.jpg - 2nd and 3rd experiments created entirely in Photoshop using only the Terrain layer exported from ArcMap.
As can be seen, ArcMap can create much better Hillshades than Photoshop's Lighting Effects. This is simply due to the fact that Photoshop can only use 8-bits of data (pure greyscale) where ArcMap can use full 32-bit grid files. ArcMap grid files are rasters, however each grid cell (pixel) contains 32-bits of data. This data, specifically for DEM rasters, is nothing more than a floating point number depicting elevation. Rasters in graphics programs are only long integers containing a color value, and maybe an alpha value. Although ArcMap is limited to the same number of greys as Photoshop, it still uses the 32-bits, sophisticated Color Ramps, and sophisticated algorithms for applying the color ramps. Photoshop's gradients and lighting effects just can't compare. Perhaps even Photoshop v15 (aka CS5) still couldn't come close. I do know that Photoshop 15 still cannot handle anything more than an 8-bit heightfield raster (had access at college).
I have just begun learning to use Quantum GIS (QGIS) to see if I can't get the same effects as ArcMap, but the process is slow since QGIS does not have as sophisticated a symbol editor as ArcMap. It is much easier creating a color ramp in ArcMap than I have been able to do in QGIS. But I am still trying and learning.
Also attached, I included a Photoshop GRD file with the Hypsometric Gradients I created to match the ArcMap color ramps as best as possible. Of course, you can simply move the color stops as you see fit.
I am also looking into making a DEM with Wilbur. If waldronate sees this post, I'd appreciate an answer to this: Is there a file format in Wilbur which will create a 32-bit grid file which uses floating point numbers? I will look into Wilbur's help to find this, but you might answer before I find it.
Keep watching. I'll keep posting my experiments in this topic.
Thanks for the C&C.
rmfr