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Graduated Black to Transparent ramp

November 02 2009 | 0 comments
Categories: Symbology

When using a hillshade raster generated from a DEM raster, there does not appear to be way to use a color ramp that is a varying levels of black all the way to completely transparent. (only white to black / black to white) Using graduated white to black ramp and setting the hillshade raster transparency creates a milky haze effect when the hillshade raster is placed over base features. Alternatively, setting transparency of base features and placing them above the hillshade raster creates a problem when hillshade effect needs to be s displayed over numerous overlapping layers. Graduated black to transparent would create a more dramatic feel and simpify things. Is this possible?

Mapping Center Answer:

You are correct--you can only make a color ramp from one color to another color--not to transparent. 

One trick you could do is assign layer level transparency, say to 55% and set the background color No color, and to a value of 180 (flat). 

You can also reclassify the hillshade in order to include more values than just 180 as a backround value, for instance,

0-175 (break into 10 equal interval classes)

175-185 one class (for relatively flat locations)

185-255 (break into 5 equal interval classes)

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