Let me add another thought; if you want to log distribute colors over the original data, data drive the colormap, execute once, then in the Colormap Editor window, choose Options>Axis Display>Histogram. This reveals a histogram of the data arranged vertically next to the RGB color bar on the left. Now that you now where the data "clumps" (probably near the low end), add a couple control points to the Hue curve (just double-click on it) and drag them to form an exponential curve. This will push the color distribution down into the clumped area, thus more "evenly" colorizing the data without actually changing it. The one downside to this scheme is that the Colorbar (legend) you might choose to display will be hard to read since it will tend to be mostly red, assuming you use red for higher values. The advantage is that the data remains in its original form for later operations downstream of the colorizing op.
>You will need to (1)log your data first or (2)create a log based colorscale. > >1) Just run your data through compute and enter an appropriate >expression to convert it. > >2) Create a color scale using Colormap. Take its output and >Mark(positions), then Compute on the positions using a log expression >that encompasses your data, Unmark(positions) and use this new color >field as the color input to Color. > >David > >>Hi >>Is there a quick and obvious way to use colormap to plot my 3D data on a >>log scale. Or would I have to log the data first ? >>thanks >>trudy >> >> >>~ Knowledge divides the world ~ >> ~ Wisdom makes it whole ~ >> -anonymous >> >>______________________________________________________________________________ >>_ >>Trudy A. van der Straaten email: [EMAIL >>PROTECTED] >>Visiting Postdoctoral Research Fellow phone: (217) 244 4076 >>University of Illinois at Urbana-Champaign >>Dept Electrical & Computer Engineering >>Beckman Institute Rm 3261 >>405 North Mathews Street >>Urbana IL 61801 >>______________________________________________________________________________ >>__ > >-- >............................................................................. >David L. Thompson The University of Montana >mailto:[EMAIL PROTECTED] Computer Science Department >http://www.cs.umt.edu/u/dthompsn Missoula, MT 59812 > Work Phone : (406)257-8530 Chris Pelkie Vice President/Scientific Visualization Producer Conceptual Reality Presentations, Inc. 30 West Meadow Drive Ithaca, NY 14850 [EMAIL PROTECTED]
