Multi-Color Hillshade

[@krich404]

You should do a video on how to create those crispy hillshades you mentioned on Instagram. Thanks for the great videos.

[@ibrahimmohammed3484]

Thank you john for the awesome content

[@JohnNelsonMaps]

Glad you enjoy it!

[@karenedelstein6698]

I just discovered your videos after watching the How To Do Map Stuff presentations yesterday. Fabulous insights, and a really accessible teaching style. Kudos! I'm hooked. :) My question: For many, many years, I've been trying to understand why, depending on whether the light source is 315 degrees, or 180 degrees opposite, the topography either looks "normal" or else valleys look like mountains. Similarly, why does this happen if you take a printed hillshade image and turn it upside down? Lastly, why do we interpret 315 degrees as optimal when that's never a place the sun shines from here? I hope you can (ha-ha) shed some light on this.

[@JohnNelsonMaps]

Great questions. This is called "relief inversion" and is a really old problem for cartographers. Our minds just like to perceive a light source in the "upper left corner." A recent study found that the ideal angle is actually around 320 degrees. Why? Certainly we are primed to expect light sources to be coming from "up" so that makes sense. Why left more than right? I don't know! We're crazy creatures. Really, the notion of floating high in the air (or space) and looking down on the wrinkles of our planet is sort of a new phenomenon for our brains, and we aren't hard-wired to have that perspective or a strong internal sense of "north" being "up." That's just a geographic convention (various cultures in history have had other directions associated with "up" on a map -like east in European maps of the Middle Ages, to honor Jerusalem. So just because light tends to come from the south (only in the northern hemisphere; it comes from the north for those in the southern hemisphere) it doesn't override our wiring to think of light as coming down from above. Some cartographers, Like Eduard Imhof, have been able to pull off a true southern light source without triggering relief inversion, but they are masters. It's a fascinating topic. en.wikipedia.org/wiki/Inverted_relief

[@andresimplicio2131]

Thank you!

[@JohnNelsonMaps]

Welcome!

[@andreamamusa3512]

Thank You for this tutorial! I have two questions to ask: Is it possible to achieve the same results using ArcGIS desktop? If not, from which version of ArcGIS PRO are the features to adjust the color in the hillshade function available?

[@JohnNelsonMaps]

ArcMap is extremely limited when it comes to transparency. it does not support within-gradient variations in transparency, which this makes heavy use of. it only allows to a single transparency to be applied to the whole layer, which results in comparatively drab topography. follow this video to see how to adjust color of hillshade.